Standards for communication channels. Operational standards for electrical parameters of switched channels of the PSTN network. General terms and definitions

Ministry of Communications Russian Federation

STANDARDS
on electrical parameters
digital channels and tracts
trunk and intrazonal
primary networks

The standards were developed by TsNIIS with the participation of operating enterprises of the Ministry of Communications of the Russian Federation.

General editing: Moskvitin V.D.

MINISTRY OF COMMUNICATIONS OF THE RUSSIAN FEDERATION

ORDER

10.08.96

Moscow

№ 92

On approval of the Standards for electrical parameters
main digital channels and backbone paths
and intrazonal networks of VSS of Russia

I ORDER:

1. Approve, introduce and put into effect from October 1, 1996, the “Norms for the electrical parameters of the main digital channels and paths of the backbone intra-zonal primary networks of the Russian VSS” (hereinafter referred to as the Norms).

2. To the heads of the organization:

2.1. Be guided by the Standards when commissioning and maintaining digital channels and paths of the backbone and intra-zonal primary networks of the Russian Air Force;

2.2. Prepare and send to the Central Research Institute of Communications the results of control measurements for existing digital plesiochronous transmission systems within a year from the date of introduction of the Standards.

3. Central Scientific Research Institute of Communications (Varakin):

3.1. By November 1, 1996, develop and send to organizations forms for recording the results of control measurements.

3.2. Ensure coordination of work and clarify the Standards in 1997 based on the measurement results under this order.

3.3. In 1996 - 1997, develop standards for:

slippage and propagation time in digital channels and paths of the plesiochronous digital hierarchy;

electrical parameters of digital paths of the synchronous digital hierarchy at a transmission speed of 155 Mbit/s and higher;

electrical parameters of digital channels and paths organized in analog cable and radio relay transmission systems using modems, digital channels and paths of the local primary network, satellite digital channels with transmission speeds below 64 kbit/s (32, 16 kbit/s, etc.);

reliability indicators of digital channels and paths.

3.4. To develop in 1996 a comprehensive program for carrying out work on standardization and measurement of channels and paths of a promising digital network of the OP.

4 . NTUOT (Mishenkov) to provide financing for the work specified in this order

5. The Main Directorate of State Supervision of Communications in the Russian Federation under the Ministry of Communications of the Russian Federation (Loginov) shall ensure control over the implementation of the Standards approved by this order.

6. The heads of organizations should be informed by August 15, 1996 of the need for these Standards, taking into account that they can be purchased on a contractual basis from the Resonance Association (contact phone 201-63 81, fax 209-70-43).

7. Association "Resonance" (Pankov) (by agreement) to replicate the Standards for the electrical parameters of the main digital channels and paths of the backbone and intra-zonal primary networks of the VSS of Russia

8. Entrust control over the implementation of the order to the UES (Rokotyan).

Federal Minister V Bulgak

LIST OF ABBREVIATIONS, CONVENTIONS,
CHARACTERS

ASTE- automated system technical operation

VZPS- intrazonal primary network

VC- built-in control

FOCL- fiber-optic communication line

VOSP- fiber-optic transmission system

Supreme Soviet of the Russian Federation- interconnected communication network of the Russian Federation

VTsST- secondary digital network path

BCC- main digital channel

PCI- plesiochronic digital hierarchy

PCST- primary digital network path

PSP- pseudo-random sequence

RSP- radio relay transmission system

SMP- primary backbone network

SSP- satellite transmission system

SDH- synchronous digital hierarchy

TCST- tertiary digital network path

DSP- digital transmission system

CST- digital network path

CCST- quaternary digital network path

AIS (alarm indication signal)- emergency indication signal

BER (bit error ratio)- bit error rate

BIS (bringing-into-service)- commissioning

BISO (bringing-into-service objective)- BIS norm

RPO (reference performance objective)- reference standard for technical characteristics

PO (performance objective)- standards for technical characteristics

ES (errored second)- second with errors

SES (severely errored second)- error-stricken second

LOF (loss of frame)- cycle loss

LOS (loss of signal)- signal loss

FAS (frame alignment signal)- cyclic synchronization signal

1. TERMS AND DEFINITIONS

1.1. General terms and definitions

1) Main digital channel(basic digital circuit) - Typical digital transmission channel with a signal transmission rate of 64 kbit/s

2) Transmission channel(transmission circuit) - A set of technical means and distribution environment that ensures the transmission of a telecommunication signal in a frequency band or at a transmission rate characteristic of a given transmission channel between network stations, network nodes or between a network station and a network node, as well as between a network station or network node and terminal device of the primary network

Notes:

1. The transmission channel is given a name analog or digital depending on the methods of transmission of telecommunication signals.

2. A transmission channel in which analogue or digital methods of transmitting telecommunication signals are used in its different sections is given the name mixed transmission channel.

3. The digital channel, depending on the transmission speed of telecommunication signals, is given a name basic,primary,secondary,tertiary,quaternary.

3) Typical transmission channel(typical transmission circuit) - Transmission channel, the parameters of which comply with the standards of the VSS RF

4) Voice channel(voice frequency transmission circuit) - Typical analog transmission channel with a frequency band from 300 to 3400 Hz

Notes:

1. If there are transits via PM, the channel is called composite, in the absence of transits - simple.

2. If there are sections in the composite channel PM, organized both in cable transmission systems and in radio relays, the channel is called combined.

5) Telecommunication channel, bearer channel(telecommunication circuit, bearer circuit) - The path of telecommunication signals formed by sequentially connected channels and lines of a secondary network using stations and nodes of the secondary network, ensuring, when subscriber terminals (terminals) are connected to its ends, the transmission of a message from the source to the recipient (recipients)

Notes:

1. The telecommunication channel is given names depending on the type of communication network, for example, telephone channel(communications), telegraph channel(communications), data channel.

2. By territorial basis, telecommunication channels are divided into intercity, zonal, local.

6) Transmission line(transmission line) - A set of linear paths of transmission systems and (or) standard physical circuits that have common linear structures, their service devices and the same distribution medium within the range of service devices.

Notes:

1. Transmission lines are given names depending on:

from the primary network to which it belongs: mainline, intrazonal, local;

from the distribution environment, for example, cable, radio relay, satellite.

2. A transmission line, which is a serial connection of transmission lines different in the propagation medium, is given the name combined.

7) Subscriber transmission line (primary network)(subscriber line) - A transmission line connecting a network station or network node and the terminal device of the primary network.

8) Connecting transmission line - A transmission line connecting a network station and a network node or two network stations to each other.

Note.The connecting line is given names depending on the primary network to which it belongs: trunk, intrazonal, local.

9) Primary network(transmission network, transmission media) - A set of standard physical circuits, standard transmission channels and network paths, formed on the basis of network nodes, network stations, terminal devices of the primary network and transmission lines connecting them.

10) Primary intrazonal network- Part of the primary network that provides interconnection of standard transmission channels of different local primary networks of the same telephone network numbering zone.

11) Primary backbone network- Part of the primary network that provides interconnection of standard transmission channels and network paths of different intra-zonal primary networks throughout the country.

12) Primary local network- Part of the primary network limited to a metropolitan or rural area.

Note. The local primary network is given names: urban (combined) or rural primary network.

13) Interconnected communication network of the Russian Federation (VSS RF)- A complex of technologically interconnected telecommunication networks on the territory of the Russian Federation, provided with general centralized management.

14) Transmission system(transmission system) - A set of technical means that ensure the formation of a linear path, standard group paths and transmission channels of the primary network.

Notes:

1. Depending on the type of signals transmitted in the linear path, the transmission system is given names: analog or digital.

2. Depending on the medium of propagation of telecommunication signals, the transmission system is given names: wired transmission system and radio system transfers.

15) Wire transmission system- A transmission system in which telecommunication signals are propagated by electromagnetic waves along a continuous guide medium.

16) Group path(group link) - A set of technical means of a transmission system designed for transmitting telecommunication signals of a normalized number of voice frequency channels or basic digital channels in a frequency band or at a transmission rate characteristic of a given group link.

Note: The group path, depending on the normalized number of channels, is given a name: primary, secondary, tertiary, quaternary or Nth group path.

17) Typical group path(typical group link) - A group path, the structure and parameters of which comply with the standards of the Armed Forces of the Russian Federation.

18) Network path(network link) - A typical group path or several serially connected standard group paths with path formation equipment enabled at the input and output.

Notes:

1. If there are transits of the same order as a given network path, the network path is called composite, in the absence of such transits - simple.

2. If there are sections in a composite network path organized both in cable transmission systems and in radio relays, the path is called combined.

3. Depending on the method of signal transmission, the path is given a name analog or digital.

19) Linear transmission system path- A set of technical means of a transmission system that ensures the transmission of telecommunication signals in a frequency band or at a speed corresponding to a given transmission system.

Notes:

1. The linear path, depending on the propagation environment, is given names: cable, radio relay, satellite or combined.

2. The linear path, depending on the type of transmission system, is given names: analog or digital.

20) Transit(transit) - A connection of transmission channels or paths of the same name, ensuring the passage of telecommunication signals without changing the frequency band or transmission speed.

21) Primary network terminal device(originative network terminal) - Technical means that ensure the formation of standard physical circuits or standard transmission channels for provision to subscribers of secondary networks and other consumers.

22) Network node(network node) - A set of technical means that ensures the formation and redistribution of network paths, standard transmission channels and standard physical circuits, as well as their provision to secondary networks and individual organizations.

Notes:

1. A network node, depending on the primary network to which it belongs, is given names: mainline, intrazone, local.

2. Depending on the type of functions performed, the network node is given names: network switching node, network allocation node.

23) Physical circuit(physical circuit) - Metal wires or optical fibers that form the guiding medium for transmitting telecommunication signals.

24) Typical physical circuit(typical physical circuit) - A physical circuit whose parameters comply with the standards of the Supreme Soviet of the Russian Federation.

1.2. Definitions of error rates for BCC

1) Errored Second - ES k - a period of 1 s during which at least one error was observed.

2) Severely Errored Second - SES k - a period of 1 s during which the error rate was more than 10 -3.

3) Errored Seconds Rate (ESR) is the ratio of the number of ES to the total number of seconds in the standby period during a fixed measurement interval.

4) Error rate per second affected by SESR errors is the ratio of the number of SES to the total number of seconds in the standby period during a fixed measurement interval.

1.3. Definitions of error rates for network paths

1) Block - a sequence of bits limited in the number of bits related to a given path; each bit belongs to only one block. The number of bits in a block depends on the transmission speed and is determined using a separate method.

2) Errored Block - EB t - a block in which one or more bits included in the block are erroneous.

3) Errored Second - ES t - a period of 1 second with one or more error blocks.

4) Severely Errored Second - SES - a period of 1 second containing ³ 30% error blocks (EBs) or at least one severely disturbed period (SDP).

5) Error rate by seconds with errors - (ESR) - the ratio of the number of ES t to the total number of seconds in the standby period during a fixed measurement interval.

6) Error rate by seconds affected by SESR errors is the ratio of the number of SES t to the total number of seconds in the standby period during a fixed measurement interval.

7) Severely Disturbed Period - SDP - a period of duration equal to 4 adjacent blocks, in each of which the error rate was ³ 10 -2 or on average over 4 blocks the error rate was ³ 10 -2, or a loss of signal information was observed.

8) Block with a background error (Backround Block Error) - BBE - a block with errors that is not part of the SES.

9) Error rate for blocks with background errors ВВER - the ratio of the number of blocks with background errors to the total number of blocks during readiness for a fixed measurement interval, excluding all blocks during SES, i.e.

10) The unavailability period for one path direction is the period starting with 10 consecutive seconds of SES (these 10 seconds are considered part of the unavailability period) and ending with 10 consecutive seconds without SES (these 10 seconds are considered part of the availability period).

The period of unavailability for a path is the period when at least one of its directions is in a state of unreadiness.

2. GENERAL PROVISIONS

2.1. These Standards are intended for use by operating organizations of primary networks of the Russian Air Transport Network in the process of operating digital channels and paths and for putting them into operation.

The standards should also be used by transmission system equipment developers when determining requirements for individual types of equipment.

2.2. These standards are based on ITU-T Recommendations and studies conducted on existing networks Russian communications. The standards apply to channels and paths of the primary backbone network with a length of up to 12,500 km and intra-zonal networks with a length of up to 600 km. Compliance with the standards given below ensures the required transmission quality when organizing international connections with a length of up to 27,500 km.

2.3. The above standards apply:

On simple and composite main digital channels (BCD) with a transmission rate of 64 kbit/s,

Simple and compound digital paths with transmission speeds of 2.048 Mbit/s, 34 Mbit/s, 140 Mbit/s, organized in fiber-optic transmission systems (FOTS) and radio relay transmission systems (RST) of the synchronous digital hierarchy,

Simple and compound paths organized in modern VOSP, RSP and digital transmission systems on metal cables of the plesiochronous digital hierarchy (PDH),

To linear PDH paths, the transmission speed of which is equal to the speed of the group path of the corresponding order

2.4. Channels and paths organized in DSP on metal cable and FOTS, developed before the adoption of new ITU-T Recommendations, as well as in analog cable and radio relay transmission systems organized using modems, may have deviations in some parameters from these Standards.

Clarified standards for digital channels and paths formed in DSPs operating on the backbone network on a metal cable (ICM-480R, PSM-480S) are given in.

Clarification of the standards for digital channels and paths of DSP and VOSP, which are in operation on intra-zonal networks (“Sopka-2”, “Sopka-3”, IKM-480, IKM-120 (various modifications)), will be made based on the results of implementation within years of these Standards.

2.5. These standards develop requirements for two types of indicators of digital channels and paths - error indicators and indicators of jitter and phase drift.

2.6. Error rates of digital channels and paths are statistical parameters and the norms for them are determined with the corresponding probability of their fulfillment. The following types of operational standards have been developed for error indicators:

long-term norms

operational standards.

Long-term standards are determined based on ITU-T recommendations G.821 (for 64 kbit/s channels) and G.826 (for paths with speeds of 2048 kbit/s and above).

Checking long-term standards requires long periods of measurement under operating conditions - at least 1 month. These standards are used when checking the quality indicators of digital channels and paths of new transmission systems (or new equipment of certain types that influence these indicators), which were not previously used on the primary network of our country.

Operational standards refer to express standards; they are determined based on ITU-T recommendations M.2100, M.2110, M.2120.

Operational standards require relatively short measurement periods for their evaluation. Among the operational norms the following are distinguished:

standards for putting paths into operation,

maintenance standards,

system recovery standards.

Standards for commissioning paths are used when channels and paths formed by similar transmission system equipment are already on the network and have been tested for compliance with long-term standards. Norms Maintenance are used to monitor the operation of paths and to determine the need to take them out of operation when the monitored parameters go beyond acceptable limits. Standards for restoring systems are used when putting a path into operation after equipment repair.

2.7. Standards for jitter and phase drift include the following types of standards:

network limit norms at hierarchical junctions,

limit standards for phase jitter of digital equipment (including the characteristics of the transmission of phase jitter),

standards for phase jitter of digital sections.

These indicators are not statistical parameters and do not require lengthy measurements to verify them.

2.8. The presented standards are the first stage in the development of standards for the quality indicators of digital channels and network paths. They can be further refined based on the results of operational tests for channels and paths organized in certain types of digital processing centers. In the future, it is planned to develop the following standards for digital channels and paths:

standards for slippage and propagation time in digital channels and PDH paths,

standards for electrical parameters of SDH digital paths at speeds of 155 Mbit/s and higher,

standards for reliability indicators of digital channels and paths,

standards for electrical parameters of digital channels and paths of the local primary network,

standards for the electrical parameters of digital channels with transmission speeds below 64 kbit/s (32; 16; 8; 4.8; 2.4 kbit/s, etc.).

3. GENERAL CHARACTERISTICS OF DIGITAL
CHANNELS AND TRACTS

General characteristics of the central circulation center and network digital paths of the plesiochronous digital hierarchy are given in.

Table 3.1

General characteristics of the main digital channel and network
digital paths of the plesiochronous digital hierarchy

No.	Type of channel and tract	Nominal transmission speed, kbit/s	Transmission speed deviation limits, kbit/s	Nominal input and output resistance, Ohm
	Main digital channel		± 5·10 -5	120 (sim)
	Primary digital network path	2048	± 5·10 -5	120 (sim)
	Secondary digital network path	8448	± 3·10 -5	75 (carry)
	Tertiary digital network path	34368	± 2·10 -5	75 (carry)
	Quad digital network path	139264	± 1.5·10 -5	75 (carry)

4. STANDARDS FOR ERROR RATES
DIGITAL CHANNELS AND NETWORK TRACTS

4.1. Long-term standards for error rates

4.1.1. Long-term standards for BCC are based on measuring error characteristics over second-by-second time intervals using two indicators:

error rate per second with errors (ESR k),

error rate per second affected by errors (SESR k).

In this case, the definitions of ES and SES correspond to .

Measurements of error rates in the BCC to assess compliance with long-term standards are carried out by closing the connection and using a pseudo-random digital sequence.

4.1.2. Long-term standards for digital network paths (DNT) are based on measuring block-by-block error characteristics (see) for three indicators:

error rate by errored seconds (ESR t),

error rate per second affected by errors (SESR t),

block error rate with background errors (BBER t).

It is assumed that when meeting the standards in the DST for error indicators based on blocks, the long-term standards in the BCC formed in these DSTs for error indicators based on second intervals will be ensured.

Measurements of error rates in DPTs to assess compliance with long-term standards can be carried out either at the close of communication using a pseudo-random digital sequence, or during operational monitoring.

4.1.3. The BCC is considered to comply with the standards if each of the two error indicators meets the requirements - ESR k and SESR k. The network path is considered to comply with the standards if each of the three error indicators meets the requirements - ESR t, SESR t, and BBER t.

4.1.4. To assess operational characteristics, measurement results should be used only during periods of availability of a channel or path; intervals of unavailability are excluded from consideration (for the definition of unavailability, see).

4.1.5. The basis for determining the long-term norms of a particular channel or path are the general calculated (reference) norms for a complete connection (end-to-end) for the error rates of an international connection with a length of 27,500 km, given in columns A for the corresponding error rate and the corresponding digital channel or tract.

4.1.6. The distribution of maximum calculated norms for error indicators along sections of the path (channel) of the primary network of the Russian Air Transport Network is given in the column “long-term norms”, where A is taken for the corresponding error indicator and the corresponding path (channel) from the data.

4.1.7. The share of calculated operational standards for error rates for a path (channel) of length L on the backbone and intra-zonal primary networks of the Russian Air Force for determining long-term standards is given in.

Table 4.1

General design operating standards for error rates
for an international connection of 27,500 km

Type of tract (channel)	Speed, kbit/s	A			IN
		Long-term norms			Operating standards
		ESR	SESR	BBE R	ESR	SESR
BCC		0,08	0,002		0,04	0,001
PCST	2048	0,04	0,002	3·10 -4	0,02	0,001
VTsST	8448	0,05	0,002	2·10 -4	0,025	0,001
TCST	34368	0,075	0,002	2·10 -4	0,0375	0,001
CCST	139264	0,16	0,002	2·10 -4	0,08	0,001
Note. The data given for long-term standards correspond to ITU-T Recommendations G .821 (for a 64 kbit/s channel) and G.826 (for paths with speeds from 2048 kbit/s and higher), for operational standards - ITU-T Recommendations M.2100.

Table 4.2

Distribution of limit norms for error rates
along sections of the tract (channel) of the primary network

Type of tract (channel)

Plot

Length, km

Long-term norms

Operating standards

ESR

SESR

BBER

ESR

SESR

BCC

Ab. lin

0.15 A

0.15 A/2

0.15 V

Ministry of Railways

0.075 A

0.075 A/2

0.075 V

VZPS

0.075 A

0.075 A/2

0.075 V

SMP

12500

0.2 A

0.2 A/2

0.2 V

CST

Ministry of Railways

0.075 A

0.075 A/2

0.075 A

0.075 V

VZPS

0.075 A

0.075 A/2

0.075 A

0.075 V

SMP

12500

0.2 A

0.2 A/2

0.2 A

0.2 V

Notes:

1. To the specified limit value of the long-term norm for the indicator SESR, when included in a tract or channel of the NSR, a section with a RSP length of L = 2500 km, a value equal to 0.05% is added, with one section with a RSP - a value of 0.01%. These values take into account unfavorable signal propagation conditions (in the worst month).

4.1.11. If a channel or tract passes through both the SMP and the VZPS, then the value of C for the entire channel is determined by summing the values of C 1 and C 2 (for both ends):

and then the norm for the corresponding parameter is determined.

Example 3. Let it be necessary to determine the norms of the ESR and SESR indicators for a central circulation channel passing along the NSR with a length of L 1 = 830 km, and along two high-voltage transport links with a length of L 2 = 190 km and L 3 = 450 km, organized via fiber optic links in all three sections. We find the values of A:

We round the length L 1 to a multiple of 250 km, the length L 2 to a multiple of 50 km, and L 3 to a multiple of 100 km:

4.2. Operational standards for error rates

4.2.1. General Statements for Defining Operating Standards

1) Operational standards for error indicators of the BCC and DST are based on measuring error characteristics over second-by-second time intervals using two indicators:

Errored Seconds Rate (ESR),

Error Seconds Error Rate (SESR).

At the same time, for bcc the definitions ES and SES correspond, and for CST - .

Measurements of error rates in DPTs to assess compliance with operational standards can be carried out both during operational control and when closing communications using special means measurements. Measurements of error rates in the OCC to assess compliance with operational standards are carried out when the connection is closed. The measurement technique is given in.

2) BCC or DCT are considered to comply with operational standards if each of the error indicators - ESR and SESR - meets the specified requirements.

3) To assess operational characteristics, measurement results should be used only during periods of availability of the channel or path; intervals of unavailability are excluded from consideration (see definitions of unavailability).

4) The basis for determining the operational standards for a link or path are the overall end-to-end error rate estimates for a 27,500 km international connection, given in Columns B for the corresponding error rate and the corresponding digital channel or path.

5) The distribution of the maximum calculated standards for error indicators along sections of the path (channel) of the primary network of the Russian Air Force is given in the column “operational standards”, where B is taken for the corresponding error indicator and the corresponding path (channel) from the data.

6) The share of calculated operational standards for path (channel) error indicators with a length of L km on the backbone and intra-zonal primary networks of the Russian Air Force for determining operational standards is given in. This share for the tract (channel) of the SMP is designated D 1 and for the VZPS - D 2.

Length L of the tract (channel) on the NSR at L< 1000 км округляется до значения L 1 , кратного 250 км в большую сторону, при L >1000 km - a multiple of 500 km, on the VZPS at L< 200 км - до значения, кратного 50 км, при L >200 km is a multiple of 100 km. When L > 2500 km for a channel (tract) SMP D 1 is determined by interpolation between neighboring values or by the formula:

7) The procedure for determining the value of D for a simple BCC or DCT is as follows:

the length L of the channel (path) is rounded to the values specified in,

for the found value of L 1 we determine the value of D 1 or D 2.

For a composite bcc or cst, the calculation procedure is as follows:

the length L i of each transit section is rounded to the values specified in ,

for each section is determined by the value of D i,

the obtained values of D i are summed up:

The resulting total value of D should not exceed 20% for the SMP, 7.5% for the VZPS, and 35% for a channel or tract passing through the SMP and two VZPS.

Table 44

Share of operational standards for error indicators for a site
path (channel) length L km on the main and intra-zonal
primary networks of the VSS of Russia to determine operational standards

SMP			VZPS
No.	Length, km	D	No.	Length, km	D 2
	£250	0,015		£50	0,023
	£500	0,020		£100	0,030
	£750	0,025		£150	0,039
	£1000	0,030		£200	0,048
	£1500	0,038		£300	0,055
	£2000	0,045		£400	0,059
	£2500	0,050		£500	0,063
	£5000	0,080		£600	0,0750
	£7500	0,110
	£10,000	0,140
	£12,500	0,170

8) If the channel or path is international, then the operational standards for it are determined in accordance with ITU-T Recommendation M.2100. To assess compliance with the standards of the M.2100 recommendation of a part of an international channel or path passing through the territory of our country, you can use the above methodology for determining standards, but instead you must use , the data of which corresponds to table. 2v/M.2100.

Table 4.5

Distribution of standards for international channels and paths

Length L, km	Share of calculation norms (% of end-to-end RPO rates)
L £ 500 km
500 km< L £ 1000 км
1000 km< L £ 2500 км
2500 km< L £ 5000 км
5000 km< L £ 7500 км
L > 7500 km	10,0

The part of the channel or path passing through the territory of our country to the international station (international switching center) must satisfy these standards.

9) Monitoring error rates in channels or paths to determine compliance with operational standards can be carried out under operating conditions for various periods of time - 15 minutes, 1 hour, 1 day, 7 days (see). To analyze the control results, threshold values S 1 and S 2 of the number of ES and SES are determined for the observation period T at T £ 1 day and one threshold value BISO at T = 7 days (the designations of threshold values are the same as in the ITU-T M recommendation .2100).

Threshold values are calculated in the following order:

The average is determined valid number ES or SES during the observation period

(1)

where D is the total value of the share of the general norm found in.

T - observation period in seconds.

B - the general norm for this indicator is taken from (for BCC ES - 4%, SES - 0.1%).

The threshold value of BISO is determined for the observation period T

(2)

where k is a coefficient determined by the purpose of operational control.

The values of the coefficient k for various test conditions of the transmission system, network path or central communication center are given in.

Threshold values S 1 and S 2 are determined by the formulas:

Table 4.6

Error Rate Limits (ES and SES)
relative to long-term reference rate

Transmission systems		Network paths, sections, central communication centers
Type of test	k	Type of test	k
Commissioning		Commissioning
Commissioning after repair	0,125	Commissioning after repair
Reduced quality input		Reduced quality input	0,75
Reference norm		Reference norm
Removal from service	> 10	Removal from service	> 10

10) If during the observation period T, based on the results of operational control, a number ES or SES equal to S is obtained, then

when S ³ S 2 - the path is not accepted for operation,

when S £ S 1 - the path is accepted for operation,

at S 1< S < S 2 - тракт принимается условно - с проведением дальнейших испытаний за более long terms.

If after additional tests(for example, 7 days), S > BISO, then the path is not accepted for operation (for more details, see).

11) In some PDH systems developed before the introduction of these standards and available on the current primary network, the error rates of channels and paths may not satisfy the given standards. Permissible deviations from the standards for individual DSPs are given in.

4.2.2. Standards for commissioning digital paths and central circulation centers

1) Standards for putting paths and central circulation centers into operation are used when channels and paths formed by similar equipment of transmission systems are already available on the network and tests have been carried out to ensure that these paths comply with the requirements of long-term standards.

2) When commissioning a linear path of a digital transmission system, measurements must be carried out using a pseudo-random digital sequence with communication closed. Measurements are carried out over 1 day or 7 days (for more details, see.

These calculations were carried out for various paths and various values of D and the results are summarized in tables. It is easy to verify that the given calculated values coincide with the data for the norm share D = 5%.

If, based on the results of the control, it turns out that it is necessary to carry out measurements within 7 days, then the threshold BISO value for this case is obtained by multiplying the unrounded BISO value for 1 day by 7.

4) If more than one network path or BCC are put into operation simultaneously, included in the same higher-order path (a higher-order network path or a linear DSP path), and this path is put into operation simultaneously with lower-order paths, then only 1 path1 of this order or the bcc is tested within 1 day, and the remaining paths are tested within 2 hours (for more details, see section 6 SES: RPO = 0, BISO = 0, S 1 = 0, S 2 = l.

5) When several network paths are commissioned as part of a single higher-order path in operation between two endpoints, and if there are operational error monitoring devices in the paths, these paths can be tested for 15 minutes each or they can all be connected sequentially along the loop and undergo testing simultaneously for 15 minutes. In this case, evaluation criteria are used for one transmission direction of one path. There shall be no ES or SES event or unavailability period during each of the 15 min test periods. In the absence of operational error monitoring devices, the check is carried out according to ).

4.2.3. Standards for maintenance of digital network paths.

1) Standards for maintenance are used to monitor paths during operation, including to determine the need to take a path out of service if error rates deteriorate significantly.

2) The path is checked during technical operation using operational error monitoring devices for periods of 15 minutes and 1 day.

3) Maintenance standards include: unacceptable quality limits - if these values are exceeded, the path must be taken out of service; reduced quality limits - if these values are exceeded, monitoring of this path and analysis of performance trends should be carried out more frequently.

4) For all specified path maintenance standards, the threshold values for ES and SES are set in accordance with the technical requirements determined by the developers of a specific type of transmission system equipment and error indicator monitoring devices, taking into account the hierarchical level of a given path and the purpose of the tests.

If these thresholds are not specified, they can be selected for degraded network path detection and decommissioning modes with a 15-minute observation period at the values given in 0

3®

4.5®

7.5®

10,0

10.5®

11,0

11.5®

13,0

13.5®

15,5

16.0®

18,5

19.0®

20,0

20.5®

21,5

22.0®

24,5

25.0®

27,0

27.5®

30,0

30.5®

33,0

33.5®

36,0

36.5®

40,0

Example 6.

The limit values for error rates when putting a path into operation after repair are determined similarly to the case of putting into operation a newly organized path (), but in this case the coefficient k is chosen equal to 0.125 for linear paths of transmission systems and equal to 0.5 for network paths and sections (see. ). Observation periods and verification procedures correspond to those given in.

5. STANDARDS FOR PHASE JITTER INDICATORS
AND PHASE DRIFT

5.1. Network limit standards for phase jitter at the output of the path

The maximum value of phase jitter at hierarchical junctions in a digital network, which must be observed under all operating conditions and regardless of the amount of equipment included in the path in front of the junction in question, must be no more than the values presented in Table. 5.1 4 , kHz

0,25

0,05

15600

2048

8448

34368

0,15

29,1

139264

0,075

3500

7,18

Notes

1. For a 64 kbit/s channel, the values given are valid for a codirectional interface only.

2. UI - unit interval.

3. B 1, and B 2 - the full swing of the phase jitter, measured at the output of bandpass filters with cutoff frequencies: lower f 1, and top f 4 and bottom f 3 and top f 4 respectively. The frequency characteristics of the filters should have a slope of 20 dB/decade.

OPERATING STANDARDS
FOR ELECTRICAL PARAMETERS
PSTN NETWORK CHANNELS

Moscow 1999

Approved

Order of the State Committee for Communications of Russia

from 5.04.99 No. 54

1. GENERAL PROVISIONS

1.1. These standards (hereinafter referred to as the Standards) apply to the electrical parameters of switched channels of local, intrazonal and long-distance PSTN networks. 1.2. Standards for the electrical parameters of switched channels of the PSTN network are given for two options for connecting measuring instruments to a switched channel: for subscribers - instead of a telephone set (in the text, subscriber - subscriber); to subscriber sets of district automatic telephone exchanges (RATS) or rural communication terminal stations (OS) (in the text RATS - RATS). 1.3. The standards contain requirements for the basic electrical parameters that have the greatest impact on the quality of telephone and documentary telecommunications. 1.4. The standards serve to assess the quality of switched channels during operational measurements. Since the switched channel provided to the subscriber for the duration of one connection consists of a large number of elements collected randomly, the parameters of this channel can be measured once, but it is almost impossible to confirm this with repeated measurements, because When you reconnect, another channel with different parameters will be organized. In this regard, not a single channel is assessed, but a set (bundle) of switched direction channels. If a non-compliance with the Standards of the direction channels is detected, the operational and technical personnel must, in accordance with the technical operation rules, take measures to search for the area and eliminate the causes of non-compliance with the Standards, using the adjustment standards for the cable and technical specifications for each type of equipment. 1.5. Assessment of compliance with the Standards of electrical parameters of direction channels is carried out using a statistical method. When measuring the parameters of several switched channels, using statistical processing of the measurement results, the probability of compliance with the Standards of the parameters of all direction channels between a pair of subscribers or a pair of automatic telephone exchanges is determined. 1.6. The necessary information about the organization of measurements, statistical processing of results and the formation of assessments of compliance of measured parameters with the Standards is given in the section “Methodology for organizing measurements and assessing compliance of measured parameters of switched channels with the Standards.”

2. OPERATING STANDARDS FOR ELECTRICAL PARAMETERS OF SWITCHED CHANNELS OF THE PSTN NETWORK

Operating standards for the electrical parameters of switched channels of the PSTN network are given in Table. 1.

Table 1 .

Electrical parameter name
	subscriber - subscriber			RATS - RATS
		intrazone.	intercity		intrazone.	intercity
1. The limit value of the residual attenuation of the channel at a frequency of 1000 (1020) Hz should not exceed, dB:
for automatic telephone exchange DS
for ATS K
for automatic telephone exchange E
2. The amplitude-frequency response of the channel is normalized at frequencies of 1800 and 2400 Hz.
The limit value of attenuation at frequencies 1800/2400 Hz should not exceed, dB:
for automatic telephone exchange DS
for ATS K
for automatic telephone exchange E
3. The signal-to-noise ratio at the output of the switched channel must be no less than, dB:
4. The range of signal phase jitter (jitter) in the frequency range 20 - 300 Hz should not exceed, degrees:
5. Cumulative exposure to transient interruptions greater than 17.0 dB in depth and duration less than 300 ms and pulsed interference with an amplitude 5 dB above the signal level, measured as a percentage of the number of seconds affected by pulsed interference and interruptions to the total number of second intervals per session measurements should not exceed, %:
for automatic telephone exchange DS
for ATS K
for automatic telephone exchange E						Table 1 P
Station type
Station type
date
Number of sessions
Quality class by parameters
Quality class by parameters
Quality class
Quality class
Table 2 P
Parameter name				Quality class
Parameter name
	Residual attenuation at 1000 (1020) Hz
	Frequency response at frequencies 1800/2400 Hz
	Signal to noise ratio
	Range of phase jitter of the transmitted signal (jitter)
	Cumulative impact of impulse noise and short-term interruptions
	NUS
	WELL IN
	Otb.

(Introduced as temporary operational standards for the electrical parameters of PSTN network channels with a validity period until 12/30/98 by order of the State Committee for Communications of Russia #74 dated 06/03/97)

GENERAL INSTRUCTIONS

1.1. These standards (draft) apply to the electrical parameters of switched telephone communication channels of the PSTN network (local, intrazonal and long-distance). Standards for the process of connection establishment (loss) and disconnection (disconnect) are contained in other regulatory documents. 1.2. The standards are given in two versions: from subscriber to subscriber and from RATS (OS) to RATS (OS), which directly includes subscribers. 1.3. These standards contain requirements for the basic electrical parameters that have the greatest impact on the characteristics of telephone and documentary telecommunications. To assess the characteristics of documentary telecommunications, a generalized, integral parameter has been introduced into the standards - the throughput of a data transmission channel organized using a modem at a speed of 2400 bit/s with error correction using the resampling method according to ITU-T Recommendations (V.22bis, V.42). 1.4. These standards serve to assess the quality of telephone communication channels during periodic operational measurements. If a non-compliance with the standards is detected, the operating personnel must, in accordance with the technical operation rules, take measures to search the area and eliminate the causes of the non-compliance, using the setting standards for each type of equipment and cable. 1.5. The assessment of compliance with the standards of channels in each direction is carried out using a statistical method. When measuring up to 15 channels with an accuracy of 0.9, the quality of all channels in a given direction between a pair of subscribers or a pair of RATS is assessed. This is achieved by special statistical processing of channel measurement results, which determines the probability of meeting the standards of all channels in a given direction. 1.6. For operational measurements of communication channels of the PSTN network, a special automated software and hardware measuring complex (SAMC) has been developed, which, according to a given program, automatically establishes connections, measures normalized parameters in the required number of channels, carries out statistical processing of the results obtained and determines the probability of compliance with the standards of the measured channel bundle. The use of a hardware-software measuring complex (HMC) significantly saves time and labor, however, measurements can also be carried out with other measuring instruments implemented in accordance with ITU-T series “O” recommendations.

2. OPERATING STANDARDS FOR ELECTRICAL PARAMETERS OF CHANNELS OF THE TF SWITCHED NETWORK (II EDITION)

The table below gives operational standards for the electrical parameters of PSTN network channels.

Table

Name of electrical parameter

Norm

Notes

2.1. The limit value of the residual attenuation between network subscribers at a frequency of 1000 (1020) Hz should not exceed:

for local (urban and rural) and area network channels (dB);

for long-distance communication channels (dB).

Including, for certain types of networks and subscribers included in certain networks and stations:

The attenuation between the telephone exchanges of the network, which includes subscribers, is normalized to a value of 10 dB less.

2.1.1. Residual attenuation at a frequency of 1000 (1020) Hz between subscribers of urban networks should not exceed the following values for networks: with seven-digit numbering (dB)

or when connecting two PBXs directly.

30,0
25,0
20,0

Same
For subscribers included in the telephone exchange, outgoing communications are 5 dB less.

2.1.2. Residual attenuation at a frequency of 1000 (1020) Hz between subscribers of rural and intrazonal networks, if the caller is included in the PBX E, should not exceed (dB).

25,0

The attenuation between telephone exchanges where subscribers are connected is normalized to a value of 10 dB less.

2.1.3. The residual attenuation at a frequency of 1000 (1020) Hz on long-distance communication channels, if the caller is connected to a telephone exchange that includes a differential system for switching to a four-wire channel, including a telephone exchange, should not exceed (dB).

26,0

Same

2.2. The amplitude-frequency response of the channel is normalized at frequencies of 1800 Hz and 2400 Hz. The limit value of attenuation at frequencies 1800/2400 between subscribers should not exceed: for channels of local (urban and rural) and zonal networks (dB);
for long-distance communication channels (dB). Including, for certain types of networks and subscribers included in certain stations.

37,0/41,0

The attenuation between the telephone exchanges of the network, which includes subscribers, is normalized to a value of 13.0/15.0 dB less.

2.2.1. Attenuation at frequencies 1800/2400 Hz. between subscribers of urban networks should not exceed the following values for networks: with seven-digit numbering (dB)
with six-digit numbering (dB)
with five-digit numbering (dB)
or when directly connecting two PBXs

37,0/41,0
31,0/35,0
25,0/29,0

The same for subscribers included in the telephone exchange, with outgoing communication it is 6/7 dB less.

2.2.2.Attenuation at frequencies 1800/2400 Hz. between subscribers of rural and intrazonal networks, if the calling subscriber is included in the telephone exchange, should not exceed (dB).

31,0/35,0

The attenuation between the telephone exchanges of the network where subscribers are included is normalized to a value of 13.0/15.0 dB less.

2.2.3.Attenuation at frequencies 1800/2400 Hz. between long-distance subscribers, if the caller is connected to a telephone exchange that includes a differential system for switching to a four-wire channel, should not exceed (dB).

32,0/36,0

Same
Same

2.3. The signal-to-noise ratio at the output of the switched channel at the subscriber or at the RATS should not be less than the following values (dB): on channels of a city, rural, or intrazonal network
on long-distance network channels
length and length > 2500 km.

25,0
20,0

When measuring subscriber-subscriber, the level of the measuring generator is 1020 Hz. should be minus 5 dBM; when measuring ATS-ATS, the generator level should be minus 10 dBM.

2.4. The range of signal phase jitter (jitter) with a frequency of 20-300 Hz, measured at the subscriber or at the RATS, should not exceed (degrees).

Same

2.5. The total impact of short-term interruptions with a depth of more than 13.0 dB and a duration of less than 300 ms and pulsed interference with an amplitude greater than the signal level, measured in fractions of second intervals affected by interruptions and pulsed interference, should not exceed (%).

For outgoing communication channels on coordinate and electronic telephone exchanges, the standard is reduced to 20% and 10%, respectively

2.6. The attenuation of the echo signal relative to the main one should not be less than the following values (dB):

When measuring from a subscriber to the opposite PBX

2.6.1. Echo of the speaker on the PBX (depending on the location of the differential system on the caller’s network:) on the PBX;
on UZSL (US, UIS);
on RATS (OS).

23,0
20,0
15,0

end of the channel, the attenuation increases by double the attenuation value of the subscriber line (2V al.).

2.6.2. Echo of the listener on the telephone exchange (depending on the location of the differential system on the calling subscriber’s network): on the telephone exchange;
on UZSL (US, UIS);
on RATS (OS).

"k" values for P = 0.9 and 0.8

Number of sessions	5	6	7	8	9	10	11	12	13	14	15
0,9	2,74	2,49	2,33	2,22	2,13	2,06	2,01	1,97	1,93	1,89	1,87
0,8	2,11	2,87	1,74	1,65	1,58	1,53	1,49	1,45	1,43	1,39	1,37

After the eighth measurement, the sum m +/- k s is compared with the standard “N” (according to Section 2); if m + k s N) measurements stop with a positive estimate; if m + k s > N (for noise immunity and throughput m -k s Notes:

With the accumulation of certain experience, the operator can vary the number of measurements to a new statistical estimate within more than 1-2 channels.
To reduce the amount of calculations, the minimum number of measured channels can be determined in advance - 15.

If after measuring 15 channels the sum m + k s > N, or for noise immunity and bandwidth m - k s 5. MEASUREMENT AND ASSESSMENT METHOD WITH THE HELP OF AUTOMATED SOFTWARE AND HARDWARE MEASURING COMPLEX "PAIK" 5.1. Measuring complexes are connected at two network stations (RATS, OS) to subscriber outputs with the corresponding number. One of the stations is outgoing, the other is incoming. The operator of the outgoing station, in accordance with the schedule or agreement, guided by the operating instructions of the PAK, draws up a measurement scenario, which determines:

telephone numbers of incoming stations where PAIC are installed.
list of measured parameters;
attributes of the measured parameters (frequencies, transmission level, measurement thresholds, etc.);
standards for measured parameters, depending on the network structure and the specifics of outgoing stations;
date, time of start and end of measurements;
time of measurement of each parameter;
maximum number of measured channels in a cycle (number of sessions);
specific characteristics when establishing a connection (interval between calls when busy, maximum number of calls, etc.);

Note. When the measurements defined by the scenario are completed and the PC is turned off, all set parameters in the scenario are saved, and when turned on the next time, only changes to the parameters should be re-entered into the scenario, in particular, phone numbers with whom the measurements should be carried out. 5.2. It is recommended to set the following attributes for typical operational measurements:

The start of measurements is no earlier than 8-10:00:00 hours;
The end of measurements is no later than 20-21:00:00 hours;
Number of measurement sessions - 15;
Pause between dials for a busy signal - 5s;
The number of attempts to get through when there is a busy signal on a local connection is 3;

when exiting the automatic telephone exchange ("8") - 10-15;
with long-distance connection - 3-10 depending
from loading long-distance channels.

Measured parameters:

Residual attenuation and frequency response at frequencies (Hz) 1020, 1800 and 2400. measurement time - 30 s.
Signal to noise ratio (ITU-T 0.132) signal - 1020 Hz, measurement time - 40 s.
Phase jitter (jitter), ITU-T recommendation 0.91 signal 1020 Hz, measurement time - 40 s.
Impulse interference and interruptions (ITU-T 0.62, 0.71) impulse interference detection threshold - at the signal level interruption detection threshold - 13 dB below the signal level control signal - 1800 Hz or 2000 Hz measurement time - 1 min.
Bandwidth -

modem according to ITU-T recommendations V.22bis, V.42
transmission speed 2400 bps.
measurement time - 1 min.

For all measurements, the level of the transmitting set generator is minus 10 dBm (for measurements between exchanges) or minus 5 dBm (for measurements between subscribers).

5.3. Standards for measured parameters are established in accordance with section 5.1. Standards for the connection establishment process: probability of connection failure - 0.1 probability of no interaction between modems - 0.1 probability of disconnection before completion of measurement - 0.05. 5.4. The scenario specified by the operator of the outgoing station is automatically transmitted to the PAK of the incoming station, which ensures the identical measurement process for each channel in both directions (when measuring the same number). 5.5. At the end of the measurement session, a table with the session number is displayed on the PC monitor screen, where for each of the measured parameters the following is presented:

given norm;
measured value;
arithmetic average (cumulative);
standard deviation (cumulative total).

5.6. At the end of the measurement cycle (with one subscriber number) after 15 sessions or when good results, with a smaller number of measurements, the channel quality class is displayed in accordance with the probability of meeting the standards P for each of the parameters:

Class I - 1.0 > P > 0.90 (0.8 - for a discrete channel)
Class II - 0.90 > P > 0.66
III class - 0.66 > P > 0.50
IV class - 0.50 > P > 0.33
V class - P

The channel quality class is determined by the probability of meeting the standards for the “worst” of the parameters. Statistical processing of the measurement results of all sessions is carried out automatically by assessing the general population using a limited sample using the “tolerance limits” method. 5.7. All measurement and statistical processing results are stored in a PC database and can be displayed on the screen and on a printer at the operator’s command. 5.8. If negative results are received for one or more parameters, operators of interacting stations can switch the PAK to analyzer mode and study one or another parameter in more detail and for a longer period of time, including with intermediate stations, which makes it possible to determine the area and reason for the low quality of channels.

“Ministry of Communications of the Russian Federation STANDARDS for the electrical parameters of digital channels and paths of backbone and intra-zonal primary networks The standards were developed by TsNIIS with the participation of...”

Ministry of Communications of the Russian Federation

on electrical parameters

digital channels and paths

trunk and intrazonal

primary networks

The standards were developed by TsNIIS with the participation of operating enterprises

Ministry of Communications of the Russian Federation.

General editing: Moskvitin V.D.

MINISTRY OF COMMUNICATIONS OF THE RUSSIAN FEDERATION

08/10/96 Moscow No. 92 I ORDER the approval of the Standards for the electrical parameters of the main digital channels and paths of the main and intra-zonal primary networks of the Russian Armed Forces.

1. Approve and put into effect from October 1, 1996 the “Norms for the electrical parameters of the main digital channels and paths of the backbone and intra-zonal primary networks of the Russian VSS” (hereinafter referred to as the Norms).

2. To heads of organizations:

2.1. Be guided by the Standards when commissioning and maintaining digital channels and paths of the backbone and intra-zonal primary networks of the VSS of Russia:

2.2. Prepare and send to the Central Research Institute of Communications the results of control measurements for existing digital plesiochronous transmission systems within a year from the date of introduction of the Standards.

3. Central Research Institute of Communications (Varakin).

3.1. By November 1, 1996, develop and send to organizations forms for recording the results of control measurements.

3.2. Ensure coordination of work and clarify the Standards in 1997 based on the measurement results under clause 2.2 of this order

3.3. In 1996–1997, develop standards for:

slippage and propagation time in digital channels and paths of the plesiochronous digital hierarchy, electrical parameters of digital paths of the synchronous digital hierarchy at a transmission speed of 155 Mbit/s and higher;

reliability indicators of digital channels and paths.

3.4. To develop in 1996 a comprehensive program for carrying out work on standardization and measurement of channels and paths of a promising digital network of the OP.

4. NTUOT (Mishenkov) to provide financing for the work specified in paragraph 3 of this order.

8. Entrust control over the implementation of the order to the UES (Rokotyan).

Federal Minister V. B. Bulgak

LIST OF ABBREVIATIONS, CONVENTIONS, SYMBOLS

ASTE - automated technical operation system VZPS - intrazonal primary network VK - built-in control of fiber optic communication line - fiber-optic communication line VOSP - fiber-optic transmission system of the VSS RF - interconnected communication network of the Russian Federation VCST - secondary digital network path OCC - main digital channel.

PDI - plesiochronous digital hierarchy PCST - primary digital network path PSP - pseudo-random sequence RSP - radio relay transmission system SMP - backbone primary network SSP - satellite transmission system SDH - synchronous digital hierarchy TCST - tertiary digital network path DSP - digital transmission system DST - digital network CCST path – quaternary digital network path

– – –

1) Basic digital circuit – A typical digital transmission channel with a signal transmission rate of 64 kbit/s.

2) Transmission circuit - A set of technical means and distribution medium that ensures the transmission of a telecommunication signal in the frequency band or at a transmission rate characteristic of a given transmission channel between network stations, network nodes or between a network station and a network node, as well as between a network station or network node and the terminal device of the primary network.

Notes:

1. The transmission channel is given the name analog or digital depending on the methods of transmitting telecommunication signals.

2. A transmission channel in which analogue or digital methods of transmitting telecommunication signals are used in its different sections is given the name mixed transmission channel.

3. The digital channel, depending on the speed of transmission of telecommunication signals, is given the name main, primary, secondary, tertiary, quaternary.

3) Typical transmission circuit – A transmission channel whose parameters comply with the standards of the VSS RF.

4) Voice frequency transmission circuit – A typical analog transmission channel with a frequency band from 300 to 3400 Hz.

Notes:

1. If there are transits along the PM, the channel is called compound, and if there are no transits, it is called simple.

2. If there are sections in a composite PM channel organized both in cable transmission systems and in radio relays, the channel is called combined.

5) Telecommunication channel, bearer circuit (telecommunication circuit, bearer circuit) – The path of transmission of telecommunication signals formed by sequentially connected channels and lines of a secondary network with the help of stations and nodes of the secondary network, ensuring the transmission of a message when subscriber terminals (terminals) are connected to its ends from source to recipient(s).

Notes:

1. The telecommunication channel is given names depending on the type of communication network, for example, telephone channel (communications), telegraph channel (communications), data channel (transmission).

2. Based on territorial characteristics, telecommunication channels are divided into long-distance, zonal, and local.

6) Transmission line – A set of linear paths of transmission systems and (or) standard physical circuits that have common linear structures, their service devices and the same propagation medium within the range of service devices.

Notes:

1. Transmission lines are given names depending on:

from the primary network to which it belongs: backbone, intrazonal, local;

from the distribution medium, for example, cable, radio relay, satellite.

2. A transmission line, which is a sequential connection of transmission lines different in the propagation medium, is given the name combined.

7) Subscriber transmission line (primary network) – A transmission line connecting a network station or network node and the terminal device of the primary network.

8) Connecting transmission line – A transmission line connecting a network station and a network node or two network stations to each other.

Note. The connecting line is given names depending on the primary network to which it belongs: trunk, intrazonal, local.

9) Primary network (transmission network, transmission media) – A set of standard physical circuits, standard transmission channels and network paths, formed on the basis of network nodes, network stations, terminal devices of the primary network and transmission lines connecting them.

10) Primary intrazonal network - Part of the primary network that provides interconnection of standard transmission channels of different local primary networks of the same telephone network numbering zone.

11) Primary backbone network – Part of the primary network that provides interconnection of standard transmission channels and network paths of different intra-zonal primary networks throughout the country.

12) Primary local network - Part of the primary network limited to the territory of a city with suburbs or a rural area.

Note. The local primary network is given names: urban (combined) or rural primary network.

13) Interconnected Communication Network of the Russian Federation (VSS RF) – A complex of technologically interconnected telecommunication networks on the territory of the Russian Federation, provided with common centralized control.

14) Transmission system – A set of technical means that ensure the formation of a linear path, standard group paths and transmission channels of the primary network.

Notes:

1. Depending on the type of signals transmitted in the linear path, the transmission system is given names: analog or digital.

2. Depending on the medium of propagation of telecommunication signals, the transmission system is given names: wired transmission system and radio transmission system.

15) Wire transmission system - A transmission system in which telecommunication signals are propagated by means of electromagnetic waves along a continuous guide medium.

16) Group link – A set of technical means of a transmission system designed for transmitting telecommunication signals of a normalized number of voice frequency channels or basic digital channels in the frequency band or at a transmission rate characteristic of a given group link.

Note. The group path, depending on the normalized number of channels, is given a name: primary, secondary, tertiary, quaternary or N-th group path.

17) Typical group link – A group link, the structure and parameters of which comply with the standards of the Armed Forces of the Russian Federation.

18) Network link (network link) – A typical group link or several series-connected standard group links with the link-forming equipment turned on at the input and output.

Notes:

1. If there are transits of the same order as a given network path, the network path is called composite; in the absence of such transits, it is called simple.

2. If there are sections in a composite network path organized both in cable transmission systems and in radio relay systems, the path is called combined.

3. Depending on the method of signal transmission, the path is given the name analog or digital.

19) Linear transmission system path – A set of technical means of a transmission system that ensures the transmission of telecommunication signals in a frequency band or at a speed corresponding to a given transmission system.

Notes:

1. Depending on the propagation medium, the linear path is given names: cable, radio relay, satellite or combined.

2. Depending on the type of transmission system, the linear path is given names: analog or digital.

20) Transit – A connection of transmission channels or paths of the same name, ensuring the passage of telecommunication signals without changing the frequency band or transmission speed.

21) Primary network terminal device – Technical means that ensure the formation of standard physical circuits or standard transmission channels for provision to subscribers of secondary networks and other consumers.

22) Network node – A set of technical means that ensures the formation and redistribution of network paths, standard transmission channels and standard physical circuits, as well as their provision to secondary networks and individual organizations.

Notes:

1. A network node, depending on the primary network to which it belongs, is given names: backbone, intrazonal, local.

2. The network node, depending on the type of functions performed, is given names: switching network node, allocation network node.

23) Physical circuit – Metal wires or optical fibers that form the guiding medium for transmitting telecommunication signals.

24) Typical physical circuit – A physical circuit whose parameters comply with the standards of the Supreme Soviet of the Russian Federation.

1.2. Definitions of error rates for BCC

1) Errored Second – ESK – a period of 1 s during which at least one error was observed.

2) Severely Errored Second – SESK – a period of 1 s during which the error rate was more than 10–3.

3) Error Seconds Rate (ESR) – the ratio of the number of ESKs to the total number of seconds in the standby period during a fixed measurement interval.

4) Error rate per second affected by SESR errors - the ratio of the number of SESK to the total number of seconds in the standby period during a fixed measurement interval.

1.3. Definitions of error rates for network paths

1) Block – a sequence of bits limited by the number of bits related to a given path; each bit belongs to only one block. The number of bits in a block depends on the transmission speed and is determined using a separate method.

2) Errored Block - EBT - a block in which one or more bits included in the block are erroneous.

3) Errored Second – EST – a period of 1 second with one or more error blocks.

4) Severely Errored Second - SEST - a period of 1 second containing 30% error blocks (EB) or at least one severely disturbed period (SDP).

5) Errored Seconds Rate (ESR) is the ratio of the number of ESTs to the total number of seconds in the standby period during a fixed measurement interval.

6) Error rate per second affected by SESR errors - the ratio of the number of SESTs to the total number of seconds in the standby period during a fixed measurement interval.

7) Severely Disturbed Period – SDP – a period of duration equal to 4 adjacent blocks, in each of which the error rate was 10–2 or on average over 4 blocks the error rate was 10–2, or a loss of signal information was observed.

8) Block with a background error (BBE) - a block with errors that is not part of the SES.

9) Error rate for blocks with background errors BBER - the ratio of the number of blocks with background errors to the total number of blocks during readiness for a fixed measurement interval, excluding all blocks during SEST.

10) The unavailability period for one path direction is the period starting with 10 consecutive seconds of SES (these 10 seconds are considered part of the unavailability period) and ending with 10 consecutive seconds without SES (these 10 seconds are considered part of the availability period).

The period of unavailability for a path is the period when at least one of its directions is in a state of unreadiness.

2. GENERAL PROVISIONS

2.1. These Standards are intended for use by operating organizations of primary networks of the Russian Air Transport Network in the process of operating digital channels and paths and for putting them into operation.

The standards should also be used by transmission system equipment developers when determining requirements for individual types of equipment.

2.2. These standards have been developed on the basis of ITU-T Recommendations and studies conducted on existing communication networks in Russia. The standards apply to channels and paths of the primary backbone network with a length of up to 12,500 km and intra-zonal networks with a length of up to 600 km. Compliance with the standards given below ensures the required transmission quality when organizing international connections with a length of up to 27,500 km.

2.3. The above standards apply:

– to simple and composite main digital channels (BCD) with a transmission rate of 64 kbit/s,

– simple and composite digital paths with transmission speeds of 2.048 Mbit/s, 34 Mbit/s, 140 Mbit/s, organized in fiber-optic transmission systems (FOTS) and radio relay transmission systems (RST) of the synchronous digital hierarchy,

– simple and compound paths organized in modern VOSP, RSP and digital transmission systems on metal cables of the plesiochronous digital hierarchy (PDH),

– to linear PDH paths, the transmission speed of which is equal to the speed of the group path of the corresponding order.

2.4. Channels and paths organized in DSP on metal cable and VOSP, developed before the adoption of new ITU-T Recommendations, as well as in analog cable and radio relay transmission systems organized using modems, may have deviations in some parameters from these Standards. Clarified standards for digital channels and paths formed in DSPs operating on the backbone network on a metal cable (ICM-480R, PSM-480S) are given in Appendix 2.

2.5. These standards develop requirements for two types of indicators of digital channels and paths - error indicators and indicators of jitter and phase drift.

2.6. Error rates of digital channels and paths are statistical parameters and the norms for them are determined with the corresponding probability of their fulfillment.

The following types of operational standards have been developed for error indicators:

long-term norms, operational norms.

Long-term standards are determined based on ITU-T recommendations G.821 (for 64 kbit/s channels) and G.826 (for paths with speeds of 2048 kbit/s and above).

Operational standards refer to express standards; they are determined based on ITU-T recommendations M.2100, M.2110, M.2120.

Operational standards require relatively short measurement periods for their evaluation. Among the operational norms the following are distinguished:

standards for putting paths into operation, standards for maintenance, standards for restoring systems.

Standards for commissioning paths are used when channels and paths formed by similar transmission system equipment are already on the network and have been tested for compliance with long-term standards. Maintenance standards are used to monitor tracts during operation and to determine the need to take them out of service when the monitored parameters go beyond acceptable limits. Standards for restoring systems are used when putting a path into operation after equipment repair.

2.7. Standards for jitter and phase drift include the following types of standards:

network limit standards at hierarchical junctions, limit standards for phase jitter of digital equipment (including characteristics of the transmission of phase jitter), standards for phase jitter of digital sections.

These indicators are not statistical parameters and long-term measurements are not required to verify them.

2.8. The presented standards are the first stage in the development of standards for the quality indicators of digital channels and network paths. They can be further refined based on the results of operational tests for channels and paths organized in certain types of digital processing centers. In the future, it is planned to develop the following standards for digital channels and paths:

standards for slippage and propagation time in digital channels and PDH paths, standards for electrical parameters of SDH digital paths at speeds of 155 Mbit/s and higher, standards for reliability indicators of digital channels and paths, standards for electrical parameters of digital channels and paths of the local primary network, standards for the electrical parameters of digital channels with transmission speeds below 64 kbit/s (32; 16; 8; 4.8; 2.4 kbit/s, etc.).

3. GENERAL CHARACTERISTICS OF DIGITAL CHANNELS AND TRACTS

General characteristics of the central circulation center and network digital paths of the plesiochronous digital hierarchy are given in Table. 3.1.

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4.1.1. Long-term standards for BCC are based on measuring error characteristics over second-by-second time intervals using two indicators:

Errored Seconds Rate (ESRK), Errored Seconds Rate (SESRK).

In this case, the definitions of ES and SES correspond to clause 1.2.

Measurements of error rates in the BCC to assess compliance with long-term standards are carried out by closing the connection and using a pseudo-random digital sequence.

4.1.2. Long-term standards for digital network paths (DNT) are based on measuring block-by-block error characteristics (see definitions in clause 1.3) for three indicators:

Errored Seconds Rate (ESRT), Errored Seconds Rate (SESRT), Errored Blocks Error Rate (BBERT). It is assumed that when meeting the standards in the DST for error indicators based on blocks, the long-term standards in the BCC formed in these DSTs for error indicators based on second intervals will be ensured.

4.1.3. The BCC is considered to comply with the standards if each of the two error indicators – ESRK and SESRK – meets the specified requirements. A network path is considered compliant if it meets the requirements of each of the three error indicators - ESRT, SESRT and BBERT.

4.1.4. To assess operational characteristics, measurement results should be used only during periods of availability of a channel or path; intervals of unavailability are excluded from consideration (for the definition of unavailability, see clause 1.3).

4.1.5. The basis for determining the long-term standards of a particular channel or path are the general calculated (reference) standards for a complete connection (end-to-end) for error rates of an international connection, with a length of 27,500 km, given in Table. 4.1 in columns A for the corresponding error rate and the corresponding digital channel or path.

4.1.6. The distribution of maximum design standards for error rates across sections of the path (channel) of the primary network of the Russian Air Transport Network is given in Table. 4.2, column “long-term norms”, where A is taken for the corresponding error indicator and the corresponding path (channel) from the data in table. 4.1.

4.1.7. The share of calculated operational standards for error rates for a path (channel) of length L on the backbone and intra-zonal primary networks of the Russian Air Transport Network for determining long-term standards is given in Table. 4.3.

Table 4.1 General estimated operational error rates for an international connection with a length of 27,500 km

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Note: The data given for long-term standards correspond to ITU-T Recommendations G.821 (for a 64 kbit/s channel) and G.826 (for paths with speeds of 2048 kbit/s and higher), for operational standards – ITU-T Recommendation M.2100.

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Notes:

1. To the specified limit value of the long-term norm for the SESR indicator, when including a section with a RSP with a length of L = 2500 km in a tract or canal of the NSR, a value equal to 0.05% is added, for one section with a NSR - a value of 0.01%. These values take into account unfavorable signal propagation conditions (in the worst month).

2. Similar to point 1, adding values to operational standards is not carried out due to the short measurement period.

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The share of operational standards for error indicators for a section of a path (channel) with a length of L km on the backbone and intra-zonal primary networks of the Russian Air Transport Network to determine long-term standards

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4.1.8. The procedure for calculating the long-term norm for any error indicator for a simple path (channel) of length L km, organized in a fiber-optic line or digital distribution network, is as follows:

according to table 4.1 for the corresponding channel or path and the corresponding error indicator we find the value A;

the value of L is rounded with an accuracy of 250 km for the SMP at L 1000 km and up to 500 km at L 1000 km, for the VZPS with L 200 km we round up with an accuracy of 50 km and for L 200 km – up to 100 km (up), we get the value L1;

for the obtained value L1 according to the table. 4.3 we determine the permissible share of the calculated norms C1 or C2 at L1 2500 km on the NSR, the share of the norm is determined by interpolation between two adjacent values of the table. 4.3 or by the formula: L1 x 0.016 x 10–3 for SMP or L1 x 0.125 x 10–3 for VZPS;

for ESR and BBER indicators, the long-term norm is determined by multiplying the values of A and C:

ESRd=A · C BBERd= A · C For the SESR indicator, the long-term rate is determined by multiplying the values

A/2 and C:

SESRd= A/2 · C.

Example 1. Let it be necessary to determine long-term standards for the ESRT and BBERT indicators for a digital primary network path organized on the NSR, in PDI systems via fiber optic links, with a length of 1415 km.

According to the table 4.1 we find the values of A for PCST:

A(ESRT) = 0.04 A(BBERT) = 3 x 10–4.

The value of L is rounded to a multiple of 500 km:

We determine long-term standards:

ESRd = 0.04 x 0.024 = 0.96 x 10–3 BBERd = 3 x 10–4 x 0.024 = 7.2 x 10–6.

4.1.9. If a canal or NSR tract contains a section of RSP with a length of up to L = 2500 km, a value equal to 0.05% is added to the specified limit value of the long-term norm for the SESR indicator, and for one section with a SSR - a value of 0.01%. These values take into account unfavorable signal propagation conditions (in the worst month).

Example 2. Let it be necessary to determine the long-term norm for the SESRT indicator for a digital secondary network path organized on the NSR in PDI systems with a fiber-optic link section with a length of 1415 km and with a section of the path organized in a new digital distribution center with a length of 930 km.

According to the table 4.1 we find the values of A for VCST:

A(SESRT) = 0.002 The value of L is rounded to values that are multiples of 500 km for fiber optic lines and multiples of 250 km for

L1FOCL = 1500 km L1РПП = 1000 km The total length of the path is rounded to a multiple of 500 km.

LFOCL + LRSP = 1415 + 930 = 2345 km L1 = 2500 km

According to the table 4.3 we determine the values of C:

SVOLS = 0.024 SRSP = 0.016 C = 0.04

We determine long-term norms for the SESRT indicator:

SESRd FOCL = 0.001 x 0.024 = 2.4 x 10–5 SESRd RSP = 0.001 x 0.016 + 0.0005 = 51.6 x 10–5 in the worst month SESRd = 0.001 x 0.04 + 0.0005 = 54 x 10 -5 in the worst month.

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Example 3. Let it be necessary to determine the norms of the ESR and SESR indicators for a central circulation channel passing along the NSR with a length of L1 = 830 km, and along two high-voltage transport links with a length of L2 = 190 km and L3 = 450 km, organized via fiber optic links in all three sections.

According to the table 4.1 we find the values of A:

A(ESRК) = 0.08 A(SESRК) = 0.002 We round the length of L1 to a multiple of 250 km, the length of L2 to a multiple of 50 km, and L3 to a multiple of 100 km:

L11 = 1000 km L12 = 200 km L13 = 500 km

According to the table 4.3 we find the value of C:

C1 = 0.016 C21 = 0.025 C22 = 0.0625

We determine long-term standards for areas:

ESRD1 = 0.08 x 0.016 = 1.28 x 10–3 ESRD2 = 0.08 x 0.025 = 2 x 10–3 ESRD3 = 0.08 x 0.0625 = 5 x 10–3 SESRD1 = 0.001 x 0.016 = 1 .6 x 10–5 SESRD2 = 0.001 x 0.025 = 2.5 x 10–5 SESRD3 = 0.001 x 0.0625 = 6.25 x 10–5

For the entire channel, the norm is determined as follows:

C = 0.016 + 0.025 + 0.0625 = 0.1035 ESRD = 0.08 x 0.1035 = 8.28 x 10–3 SESRD = 0.001 x 0.1035 = 10.35 x 10–5 4.1.12. If the channel or path is international, then long-term standards for it are determined in accordance with ITU-T recommendations G.821 (for a 64 kbit/s channel) and G.826 (for a digital path with speeds of 2048 kbit/s and higher). To assess compliance with the standards of recommendations G.821 and G.826 of a part of an international channel or path, respectively, passing through the territory of our country, you can use the above methodology for determining standards. The part of the channel or path passing through the territory of our country to the international station (international switching center) must satisfy these standards.

4.1.13. In some PDH systems developed before the introduction of these standards and available on the current primary network, the error rates of channels and paths may not satisfy the given standards. Permissible deviations from the standards for individual CBPBs are given in Appendix 2.

4.2. Operational standards for error rates

4.2.1. General provisions for defining operational standards

1) Operational standards for error indicators of the BCC and DST are based on measuring error characteristics over second-by-second time intervals using two indicators:

Errored Seconds Error Rate (ESR), Errored Seconds Error Rate (SESR).

In this case, for the BCC, the definitions of ES and SES correspond to clause 1.2, and for the CST – to clause 1.3.

Measurements of error rates in the DST to assess compliance with operational standards can be carried out both during operational control and when closing communications using special measuring instruments. Measurements of error rates in the OCC to assess compliance with operational standards are carried out when the connection is closed.

The measurement procedure is given in section 6.

2) BCC or DCT are considered to comply with operational standards if each of the error indicators – ESR and SESR – meets the specified requirements.

3) To assess operational characteristics, measurement results should be used only during periods of availability of a channel or path; intervals of unavailability are excluded from consideration (see definitions of unavailability in clause 1.3).

4) The basis for determining operational standards for a channel or path are the general design standards for a complete connection (end-to-end) for error rates for an international connection with a length of 27,500 km, given in Table. 4.1 in columns B for the corresponding error rate and the corresponding digital channel or path.

5) The distribution of maximum design standards for error rates across sections of the path (channel) of the primary network of the Russian Air Force Network is given in Table. 4.2, column “operational norms”, where B is taken for the corresponding error indicator and the corresponding path (channel) from the data in table. 4.1.

6) The share of calculated operational standards for error indicators of a path (channel) with a length of L km on the backbone and intra-zonal primary networks of the Air Force of the Russian Federation for determining operational standards is given in Table. 4.4. This share for the tract (channel) of the SMP is designated D1 and for the VPPS – D2.

The length L of the path (channel) on the NSR at L 1000 km is rounded up to the value L1, a multiple of 250 km, at L 1000 km - a multiple of 500 km, on the VZPS at L 200 km - to a value multiple of 50 km, at L 200 km – multiples of 100 km. At L 2500 km for the channel (tract) NSR D1 is determined by interpolation between adjacent values of the table.

4.4 or according to the formula:

L1 2500 D1 = 0.05 + 0.006.

7) The procedure for determining the value of D for a simple bcc or cst is as follows:

the length L of the channel (path) is rounded to the values specified in paragraph 6), for the found value of L1 we determine it from the table. 4.4 value D1 or D2.

For a composite bcc or cst, the calculation procedure is as follows:

the length Li of each transit section is rounded to the values specified in clause 6), for each section is determined according to the table. 4.4 Di value, the obtained Di values are summed up:

i =1 The resulting total value of D should not exceed 20% for the SMP, 7.5% for the VPPS, and 35% for a channel or tract passing through the SMP and two VPPSs.

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The share of operational standards for error indicators for a section of a tract (channel) with a length of L km on the backbone and intra-zonal primary networks of the Russian Air Force to determine operational standards

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8) If the channel or path is international, then the operational standards for it are determined in accordance with ITU-T Recommendation M.2100. To assess compliance with the standards of the M.2100 recommendation of a part of an international channel or path passing through the territory of our country, you can use the above methodology for determining standards, but instead of Table. 4.4 you need to use table. 4.5, the data of which corresponds to table. 2v/M.2100.

Table 4.5

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4.2.2. Standards for commissioning digital paths and central circulation centers

1) Standards for putting paths and BCC into operation are used when channels and paths formed by similar equipment of transmission systems are already available on the network and tests have been carried out to ensure that these paths comply with the requirements of long-term standards.

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3) When commissioning a network path or central communication center, the check is carried out in 2 stages.

In stage 1, measurements are carried out using a pseudo-random digital sequence for 15 minutes. If at least one ES or SES event is observed, or unavailability is observed, then the measurement is repeated up to 2 times. If ES or SES were observed during the third attempt, then the failure must be localized.

If stage 1 was successful, then the test is carried out within 1 day. These tests can be carried out using performance monitoring devices, but can also be carried out using a pseudo-random digital sequence (see Section 6 for details).

The calculated values of S1, S2 and BISO are given in tables 1.1, 2.1, 3.1, 4.1, 5.1 of Appendix 1.

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These calculations were carried out for various paths and different values of D and the results are summarized in the tables of Appendix 1. It is easy to verify that the given calculated values coincide with the data in table. 2.1 Appendix 1 for the norm share D = 5%.

4) If more than one network path or BCC are put into operation simultaneously, included in the same path of a higher order (a network path of a higher order or a linear path of the DSP), and this path is put into operation simultaneously with paths of a lower order, then only 1 path of a given order or BCC is tested within 1 day, and the remaining paths are tested within 2 hours (for more details, see Section 6).

The calculation results for S1 and S2 for test periods of 2 hours are given in Tables 1.2, 2.2, 3.2, 4.2, 5.2 of Appendix 1.

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5) When putting into operation several network paths that are part of one higher-order path in operation between two endpoints, and if there are operational error monitoring devices in the paths, these paths can be checked for 15 minutes each or can be all are connected in series via a loop and are tested simultaneously for 15 minutes.

In this case, evaluation criteria are used for one transmission direction of one path.

There shall be no ES or SES event or unavailability period during each of the 15 min test periods. If there are no operational error monitoring devices, the check is carried out according to clause 4). (See section 6 for details).

4.2.3. Standards for maintenance of digital network paths,

1) Standards for maintenance are used to monitor paths during operation, including to determine the need to take a path out of service if error rates deteriorate significantly.

2) The path is checked during technical operation using operational error monitoring devices for periods of 15 minutes and 1 day.

3) Standards for maintenance include:

limit values of unacceptable quality - if these values are exceeded, the path must be taken out of service; limit values of reduced quality - if these values are exceeded, monitoring of this path and analysis of trends in characteristics changes should be carried out more often.

4) For all specified path maintenance standards, threshold values for ES and SES are set in accordance with the technical requirements determined by the developers of a specific type of transmission system equipment and error indicator monitoring devices, taking into account the hierarchical level of a given path and the purpose of the tests.

If these threshold values are not specified, then they can be selected for modes for identifying a network path with reduced quality and for determining the need for decommissioning with a 15-minute observation period at the level of the values given in Table. 4.7.

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4.2.4. Standards for restoring paths Limit values for error rates when putting a path into operation after repair are determined similarly to the case of putting into operation a newly organized path (clause 4.2.2), but in this case the coefficient k is chosen equal to 0.125 for linear paths of transmission systems and equal to 0, 5 for network paths and sections (see Table 4.6). The observation periods and verification procedure correspond to those given in clause 4.2.2.

5. STANDARDS FOR PHASE JITTER AND PHASE DRIFT

5.1. Network limit standards for phase jitter at the path output The maximum value of phase jitter at hierarchical junctions in a digital network, which must be observed under all operating conditions and regardless of the amount of equipment included in the path in front of the junction in question, must be no more than the values presented in Table. 5.1. Measurements should be carried out according to the diagram in Fig. 5.1, the values of the filter cutoff frequencies are given in table. 5.1.

5.2. Network limits for phase drift

The network limit for phase drift at any hierarchical junction has not been defined and needs to be developed further. However, the following limit values are defined for network node interfaces.

The maximum time interval error (MOVI) at the junctions of any network nodes during an observation period of S seconds should not exceed:

a) for S 104 - this area requires further study,

b) for S 104 – (102 · S + 10000) ns.

Notes

1. MOVI is the maximum range of changes in the delay time of a given timing signal, determined between two peak deviations relative to the ideal timing signal during a certain period of time S, i.e. MOVI(S) = max x(t) - min x(t) for all t within S (Fig. 5.2).

2. The general requirements arising from this are presented in Fig. 5.3.

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Notes

1. For a 64 kbit/s channel, the values given are valid for a codirectional interface only.

2. UI – unit interval.

3. B1 and B2 – full swing of phase jitter, measured at the output of bandpass filters with cutoff frequencies: lower f1 and upper f4 and lower f3 and upper f4, respectively. The frequency characteristics of the filters should have a slope of 20 dB/decade.

5.3. Limits for phase jitter of digital equipment

a) Tolerance for jitter and phase drift on digital inputs Any digital equipment of various hierarchical levels must, without significant deterioration in the operation of the equipment, withstand at its input a digital pseudo-random test signal modulated by sinusoidal drift and phase jitter with an amplitude-frequency dependence defined in Fig. 5.4, and with the limit standards given in table. 5.2.

b) Maximum output jitter in the absence of input jitter The maximum phase jitter generated by individual types of equipment in the absence of phase jitter at its input should be determined by the requirements for specific types of equipment. In any case, these standards should not exceed the maximum permissible network standards.

c) Jitter and wander transmission characteristics Jitter transmission characteristics determine the frequency dependence of the ratio of the output jitter amplitude to the input jitter amplitude for a given transmission speed. A typical jitter transmission characteristic is shown in Fig. 5.5. The values of levels x and y and frequencies f1, f5, f6, f7 are determined in the requirements for specific types of equipment. In any case, the standard for the transmission gain level (x) should not exceed 1 dB.

Notes

1. The standard for the characteristics of the transmission of phase jitter is given for the purpose of accumulating statistical material and can be further clarified.

2. The standard for the phase drift transmission characteristics is subject to development.

5.4. Standards for phase jitter of digital sections

The jitter standards apply to conventional reference digital sections of 280 km on the backbone network and 50 km on the intra-area network. These standards are based on the assumption that only a few digital sections can be connected in series and that jitter from asynchronous multiplexing equipment is not taken into account. If these conditions are not met on actual paths, more stringent regulations may be required and/or other means of minimizing jitter may be required. Standards for this case are to be developed.

Limit standards for digital sections must be observed in all sections, regardless of the length and number of regenerators, and also regardless of the type of transmitted signal / Table 5.2 Values of tolerance parameters for jitter and phase drift at the input of the path

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Notes 1. For bcc, valid only for a co-directional joint.

2. The A0 value (18 µs) represents the relative phase deviation of the incoming signal relative to its own timing signal obtained using the reference master oscillator. The absolute value of A0 is 21 µs at the node input (that is, at the equipment input), assuming that the maximum drift of the transmission path between two nodes is 11 µs. A difference of 3 µs corresponds to a 3 µs tolerance for long-term phase deviation of the national reference master oscillator (Recommendation G.811, 3 s) * – Values are being studied.

a) Lower limit of acceptable input jitter.

It is necessary to comply with the requirements given in clause 5.3a (Fig. 5.4 and Table 5.2).

6) Characteristics of jitter transmission.

The maximum jitter transfer function gain should not exceed 1 dB.

Notes

1. The lower frequency limit should be as low as possible given the limitations of the measuring equipment (a value of approximately 5 Hz is considered acceptable).

2. For linear sections with a speed of 2048 kbit/s on an intra-zonal network, a higher value of the jitter gain is allowed - 3 dB (the limit value is subject to clarification).

c) Output jitter in the absence of input jitter. The maximum full swing of the phase jitter at the output of the digital section in the absence of phase jitter at the input for any possible signal state should not exceed the values given in Table. 5.3.

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Rice. 5.2 Determination of the maximum error of the time interval Fig. 5.3 Dependence of the maximum permissible time interval error (MATI) at the output of a network node on the observation period

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6.1.1. The measurement methods presented in this section apply to the main digital channel (DCC), primary, secondary, tertiary and quaternary digital network paths.

6.1.2. Measurement methods are given for two standardized parameters: error rates and jitter in sections 6.2 and 6.3, respectively.

6.1.3. Measurements of digital channels and paths for compliance with standards are carried out differently depending on the maintenance function performed and can be divided into the following types: measurements for compliance with long-term standards; measurements when putting paths into operation; measurements during maintenance.

6.1.4. Measurements for compliance with long-term standards are carried out during the acceptance of channels and paths formed in new transmission systems that have not previously been used on the Russian VSS network; usually such measurements are carried out simultaneously with certification tests of equipment, as well as during operational studies organized as part of work to improve operational reliability networks. These measurements are carried out according to a separate work schedule by operational personnel, production laboratories with the involvement of specialists from research institutes.

Measurements of this type are the longest and most complete. Compliance with the standards for error indicators must be assessed for at least 1 month; the measurement methodology is given in clause 6.2.1. With this type of measurement, as a rule, all standardized characteristics of phase jitter are checked in order to develop recommendations for improving the operation of paths.

6.1.5. Measurement methods during commissioning are carried out both for the cases of commissioning of digital network paths and transmission channels in new transmission systems, and for the commissioning of new paths and channels organized on existing higher-level (linear and network) paths.

6.1.6. Commissioning measurements are generally carried out only on error values over shorter periods of time. The procedure and recommendations for their implementation are given in clause 6.2.2.

When commissioning digital channels and network paths, measuring error rates is usually sufficient. But in order to accumulate statistical data on the primary network in the 1st year from the moment the standards are introduced, checking for compliance with the standards for jitter and phase drift is mandatory for this type of test.

In some cases, when putting paths into operation, it may be necessary to conduct phase jitter studies if the error rate standards are not met.

The purpose of the measurements is to ensure proper operation digital channel or network path in terms of information transmission and maintenance activities.

It is assumed that the transit sections of the digital path (simple digital paths) have already been tested for operability during the configuration process.

6.1.7 Commissioning measurements should include not only the periods of direct measurement of error indicators, described below, but also periods of operation of the equipment on the line, when the built-in control can verify that there are no violations associated with industrial activity (by industrial activity we mean anything that can negatively affect the transmission system, from maintenance activities on other equipment to vibration caused by passing traffic).

6.1.8. Commissioning tests should be carried out according to a predetermined schedule, in which it is recommended to also include periods to resolve problems that arise during measurements without disrupting the test schedule.

6.1.9. Measurements during maintenance can be carried out not only based on error indicators, although these measurements are the main ones, localization of damage begins with them.

These measurements are carried out in order to find the faulty section of the path, rack, block. Depending on the degree of coverage of the normalized parameters by monitoring built into the equipment forming the path without interrupting communication and on the type of malfunction (damage), more or less complex measurements are required with external measuring instruments. The measurement time for eliminating fairly gross damage may be short; for more complex damage, long measurement cycles may be required. Recommendations for this type of measurement are given in paragraph 6.2.3.

6.1.10. Methods for measuring digital transmission channels and digital network paths are set out in this document, based on ITU-T Recommendations, G.821, G.826, M.2100, M.2110, M.2120, O series Recommendations on the technical characteristics of measuring instruments, as well as the technical capabilities of domestic and foreign measuring equipment.

Requirements for error and jitter measurement tools are given in Section 6.4.

6.1.11. The recommended list of measuring instruments is given in Appendix 3. It contains tables with the characteristics of domestic and foreign measuring instruments and explanations for them. It should be noted that to date, only 2–3 foreign instruments fully comply with the requirements for measuring digital paths for compliance with the standards recommended by ITU-T (this applies, first of all, to the assessment of long-term standards).

The choice of instruments should be made based on the given list of measuring instruments, their technical characteristics, purpose (type of measurements) and types of paths to be measured.

6.1.12. The methodology takes into account the presence of built-in control means without interrupting communication, which are available in modern foreign and should be in promising domestic digital grouping equipment.

6.2. Methods for measuring error rates

6.2.1. Measurements for compliance with long-term standards (clause 4.1 of the Standards) 6.2.1.1. Evaluation with the termination of communication It is recommended to measure error indicators of digital channels and paths for assessing their compliance with long-term standards with the termination of communication using specialized instruments for measuring error indicators, which provide for obtaining a standardized of this type channel or path of the measurement signal in accordance with ITU-T Recommendation O.150 and error flow analysis in accordance with ITU-T Recommendations G.821 (for CCC) and G.826 (for paths with a speed of 2048 kbit/s and higher).

Definitions of error rates consistent with these Recommendations are given in Section 1.

The measurement period for assessing compliance with long-term standards must be at least 1 month, therefore the measuring instruments used for this purpose must be automated, with storage and output to a computer or registration of measurement results.

6.2.1.2. Evaluation without interruption of communication If the measured path is formed using modern equipment that has built-in monitoring tools without interruption of communication, assessing error rates for blocks of the real signal and providing information about detected anomalies and defects (see Appendix 4) to the technical operation system, where their memorization and registration (with recording the time of occurrence) and/or the development of error indicators based on them, then the assessment of the path for compliance with long-term standards can be carried out without closing the connection on the basis of this information for long periods of time (it is recommended to store this information in the technical operation system for up to 1 of the year).

If the built-in control does not provide evaluation of error rates without interrupting communication to the required extent, then it can be carried out by measuring instruments that perform these functions.

However, keep in mind that the in-line method of estimating error rates is considered less accurate (due to the possibility of missing detected events) and the off-line measurement is preferred.

6.2.2. Measurements for compliance with operational standards when putting channels and paths into operation (clause 4.2.2 of the Standards) 6.2.2.1 Error indicators of digital channels and paths to assess their compliance with commissioning standards are measured using specialized measuring instruments and/or built-in control in accordance with the procedure outlined in this section. To measure when communication is interrupted, error indicator meters should be used, which provide for receiving a measuring signal standardized for a given type of channel or path in the form pseudorandom sequence(PSP) in accordance with ITU-T Recommendation O.150 and error flow analysis in accordance with ITU-T Recommendation M.2100. For instrument requirements, see section 6.4.

If the measured path is formed using modern equipment that has built-in monitoring tools without interrupting communication, assessing error rates from a real signal in accordance with ITU-T Recommendation M.2100 and providing information about detected anomalies and defects (see Appendix 4) to the system technical operation, where their memorization, registration and generation of error indicators are ensured, then checking the path during commissioning at certain stages of the procedure described below can be carried out without closing the connection for the required periods of time.

6.2.2.2. The order of measurements and their duration are determined by the structure of the path to be tested:

transit section;

simple or compound tract;

primary or higher order tract;

the first of the paths formed in the higher order path, or the rest;

presence of a built-in control system, etc. (see below for more details).

Based on information about the path (its length, test duration), RPO standards and thresholds S1 and S2 must be determined (see commissioning standards, section 4.2). The rules for assessing error rates based on the results of measurements and control without interrupting communication are given in Appendix 4.

6.2.2.3. The measurement scheme must correspond to one of those shown in Fig. 6.1 (it is preferable to use diagrams a) and c).

6.2.2.4. Test procedure This paragraph outlines in general terms the procedure for testing digital channels and paths during commissioning (see Fig. 6.1).

It consists of the following steps:

Step 1:

Initial tests should be carried out with communication interrupted for a 15-minute period using a measuring instrument that provides a signal input to the path in the form of a signal (preferably formed in a loop) and measuring error rates (see section 6.4 for measurement requirements) . There must be no errors or unavailability during the 15 minute period. If any of these events occur, this step must be repeated again up to two times. If any of these events occur during the third (and final) test, fault isolation shall be carried out.

a) Directional measurements

– – –

c) Measurements using a crossover connector

Designations:

OA – terminal equipment;

SI – means of measurement;

DKS – digital cross-connector Fig. 6.1 Digital path measurement schemes

Designations:

VK – built-in control without interruption of communication;

SI – measuring instruments with communication interruption;

R – measurement result;

S1 and S2 – values of norms for commissioning for the corresponding assessment duration (see Appendix 1);

BISO7 – value for a 7-day period;

ST1 – values of operational standards for an assessment period of 15 minutes.

Rice. 6.2 Procedure for testing digital paths during commissioning

Step 2:

After the first step has been successfully completed, measurements are taken over a 24-hour (or other period corresponding to the given type of path) period of time. These measurements in network paths can be carried out without interrupting communication if the path formation equipment has built-in monitoring that provides an assessment of error rates. If there is no such control, the measurement is carried out using a measuring device.

If at any time during these tests an unavailability event occurs, indicated by the measuring instrument or internal controls, the cause shall be found and new tests shall be carried out. If a new failure occurs during re-testing, testing shall be suspended until the cause of the failure is eliminated.

Note. If the available technical means (measurement and control) do not allow recording cases of unavailability, it is acceptable that these requirements for cases of unavailability are not taken into account.

After the required period of time has ended, the measurement results are compared with the thresholds S1 and S2 of the norms for each parameter for a given channel or path and a given measurement duration.

The following cases are possible:

if the values of both ES and SES are less than or equal to the corresponding values of S, the path (channel) is accepted and normal operation is entered;

if the values of ES or SES (or both) are greater than or equal to the corresponding values of S2, the path (channel) is rejected and the fault localization mode is entered in accordance with the procedures given in subsection 6.2.3;

if the values of either ES or SES (or both) are greater than the corresponding values of S, but both are less than the corresponding values of S2, the path (channel) can either be accepted conditionally or be retested for the same duration, if there is no built-in control, and if it is , then the path is accepted conditionally and the tests continue up to 7 days, taking into account the first test period. At the end of repeated tests, the results are compared with the standards for a given path (channel), i.e. with BISO values for 7 days. The procedure for comparison with standards at the end of step 2 is illustrated in Fig. 6.3.

Note. If measurements are taken along a loop (scheme in Fig. 6.2b), the values of S and S2 for one direction of transmission should be considered. Under these conditions, it is impossible to assess deterioration separately by direction. If the measurements give a negative result, they are carried out again separately in each direction.

6.2.2.5. Test order and duration When commissioning a single digital path (usually a higher order, corresponding to the order of the linear path of the digital transmission system being commissioned), tests should be carried out according to the procedure described in section 6.2.2.4, and the duration of the step 2 measurements should be 24 hours .

Rice. 6.3 Limit values and conditions for commissioning

When commissioning more than one digital path at the same time, the procedure to be used depends on whether the higher order path in which the paths to be tested are formed has been in service for some time or is also new. Procedures for first-order paths also depend on whether or not there is built-in live monitoring (OC).

In Fig. 6.1 shows possible options indicating the recommended duration of the 2nd measurement step. These options are described below.

In each higher order path (with a speed higher than the primary) or transit section of such a path:

the first downstream path should be checked within 24 hours;

the remaining downstream paths of the same order are checked within one or two hours, depending on whether they are simple paths or transit sections of a composite path. In the first case, it must be checked within two hours. If a downstream path is to be connected to other transit sections to form a composite path, it must be tested within one hour and then the entire composite path between the two terminal stations of the path within 24 hours;

The first primary digital path of each higher order path must be checked within 24 hours whether there is a VC or not;

the remaining digital paths must be checked for 15 minutes each. These downstream paths can be connected in series using loopbacks and tested simultaneously within 15 minutes. If this procedure is used, there should not be a single instance of erroneous or unready seconds during the 15-minute measurement sessions.

The procedure described above also applies to BCC, taking into account the fact that it is checked only by measuring instruments without the use of built-in control means.

6.2.3. Measurements for compliance with operational standards for the maintenance of canals and tracts (clause 4.2.3 of the Standards) 6.2.3.1. General provisions During the maintenance of digital channels and network paths, measurements are carried out in the process of eliminating the causes of deteriorated quality; in their absence, measurements are not recommended.

After the introduction of ASTE ( automated system technical operation), the main role in the process of damage detection will be assigned to the continuous monitoring subsystem using built-in monitoring (IC) means without interruption of communication, which should ensure the detection of anomalies and errors without interruption of communication, evaluation of error indicators based on the information received, and their comparison with established ones thresholds, issuing signals of degraded and unacceptable quality, and identifying a damaged maintenance item. The use of measuring instruments is not required.

In the stage preceding the full implementation of the continuous monitoring subsystem (the “pre-ISM” state according to the terminology of ITU-T Recommendation M.2120), the output of standardized parameters from the long-term memory of quality indicators is not ensured. In this situation, the only option after detecting damage or disturbances in the operation of the path (through consumer complaints or monitoring means of the downstream path) is control in the subsequent period using measuring instruments. Depending on the nature of the damage, measurements are taken without interruption or with interruption of communication.

6.2.3.2. Fault Localization Procedures in Digital Paths The effectiveness of a fault localization procedure depends largely on the type of information available in the path at each bit rate (i.e.

CRC information, frame clock word, etc.).

a) Fault localization without continuous monitoring In the absence of a continuous monitoring subsystem, the fault localization process should usually begin after a user complaint.

In this situation, the only option is post-event control.

This process cannot guarantee identification of the source of the original cause of the dysfunction, especially if it is intermittent.

The main control station responsible for the damaged path must:

determine the route of the tract;

divide the path into sections. If the connection is not completely interrupted, instruments for measuring without closing the connection (for violation of the code algorithm, errors in the frame synchronization signal) in accordance with ITU-T Recommendations O.161 and O.162 (see also section 6.4), must be placed in different accessible points along the tract to determine which area is damaged. These measurements are carried out at protected control points or with instruments with a high-impedance input;

coordinate the measurement process so that the auxiliary control and transit stations begin and end measurements at the same time;

summarize the results at one point: either to the main control station, or to the point from which the damage was reported, and by comparison determine the damaged area;

make sure that there are no “white spots” in the tract for monitoring. A “white spot” is a part of the path that exists between two controlled parts (for example, distribution racks, cross-connect equipment, etc.) that is not covered by control.

If multiple areas are damaged, the location of the damage should usually be concentrated on the worst area. Where there is an additional maintenance attempt, the overall time out of service can be reduced by using this extra try. However, this process must be managed to ensure that one technician (or team) does not mask the problem that another is working on.

If the connection is completely interrupted or there are no instruments for measurements without interrupting the connection, as well as for the BCC, the same fault localization procedure described above should be applied, but with a measuring signal in the form of a PSP (if possible, formed in the form of a cycle) applied to the input of the path using appropriate error rate meter (see section 6.4).

The placement of the measurement signal input and measurement points must be selected from the point of view of the effectiveness of damage localization. This includes the possibility of loop formation.

b) Localization of damage in the presence of a continuous MONITORING subsystem The main control station of the path is informed about problems using built-in monitoring tools, long-term analysis and/or through consumer complaints.

The main control station of the tract must:

take corrective action;

confirm an unacceptable or degraded level of a path by accessing long-term memory (data obtained during commissioning, etc.) for this path.

Once procedures for localizing a fault in a digital transmission system have been initiated, the control station of the corresponding maintenance facility must provide additional information to the ASTE database from which the main control station of the network path receives information, as a result of which unnecessary actions are not taken.

If the procedure described above cannot be applied, the path route must be determined and the control stations more than high level to determine the root cause. This polling must be done directly or through a database. The information to be exchanged must be in the form of information of the quality specified in the Standards, and all events must be marked with the time and place of recording. The procedure should lead to the localization of the problem by the control station of the maintenance facility where the malfunction occurred.

6.3. Jitter Measurement Methods

6.3.1. Measuring the permissible value of input phase jitter (clauses 5.3a and 5.4a of the Standards) 6.3.1.1. General provisions Checking the operability of a digital channel or path with the maximum permissible input phase jitter is carried out by applying a measuring signal with introduced phase jitter to the input of the channel; its value and frequency are set in accordance with the standards for the maximum permissible range of sinusoidal phase jitter at the input and measuring it at the output channel or path of error indicators in accordance with the methodology of section 6.2.

The methodology for measuring the permissible value of phase jitter at the input of a digital channel, path or equipment is described in more detail below. The permissible value of phase jitter is defined as the amplitude of sinusoidal phase jitter, which, when applied to the input of a path or equipment, causes a specified deterioration in the error rate. The jitter tolerance depends on the amplitude and frequency of the applied jitter. The sinusoidal input jitter amplitudes allowed at a given frequency are defined as all amplitudes up to (but not including) the amplitude that causes the normalized error performance degradation.

The normalized degradation of the error rate can be expressed in the form of two criteria: an increase in the bit error rate (K0) and the moment of occurrence of errors. It is necessary to consider both criteria, since the tolerance for input jitter of the measured object is determined mainly by the following two factors: the ability of the timing reconstruction circuit to accurately recover the timing signal from an information signal with jitter and possibly other quality degradations (pulse distortion, transient influence , noise, etc.); the ability to withstand a dynamically changing speed of the input digital information signal (for example, the ability to digitally align and the capacity of the buffer memory for input and output from synchronization in asynchronous digital grouping equipment).

The criterion for increasing K0 makes it possible to determine (regardless of the conditions) the effect of phase jitter on the solution circuit, which is very important for assessing the first factor. The error criterion is recommended for assessing the second factor. Both methods are discussed below.

6.3.1.2. Method according to the K0 increase criterion The K0 increase criterion for measurements of the permissible value of phase jitter is defined as the amplitude of the phase jitter (at a given frequency of the phase jitter) doubling K0, which is due to a certain decrease in the signal-to-noise ratio.

The procedure of the method is divided into two stages. At the first stage, two values of K0 are determined depending on the signal-to-noise ratio at the reference points of the measured object. With zero jitter, noise is added to the signal or the signal is attenuated until the desired initial K0 is obtained. Then the noise or signal attenuation is reduced until K0 is reduced by a factor of 2.

At the second stage, at a certain frequency, phase jitter is introduced into the test signal until the initially selected value K0 is obtained. The introduced equivalent jitter provides an accurate and reproducible measure of the acceptable phase jitter of the solution circuit. The second step of the method is repeated for enough frequencies so that the measurement accurately shows a constant sinusoidal input jitter tolerance for the test object over the frequency range used. The measuring device must generate a jitter-controlled signal, obtain a controlled signal-to-noise ratio in the information signal, and measure the resulting K0 of the test object.

In Fig. Figure 6.4 shows the measurement scheme used for the method according to the K0 increase criterion. Equipment indicated by dotted lines is optional. An optional frequency synthesizer provides a more precise definition of the frequencies used for measurements. An optional jitter receiver can be used to monitor the amplitude of the generated jitter.

Operating procedure:

a) establish a connection as shown in Fig. 6.4. Check the integrity and make sure that the measured object works without errors;

b) in the absence of phase jitter, increase the noise (or weaken the signal) until at least 100 bit errors are obtained per second;

c) register the corresponding K0 and signal-to-noise ratio;

d) increase the signal-to-noise ratio by a certain amount;

e) set the input jitter frequency to the desired value;

e) adjust the amplitude of phase jitter until the initial value K0, recorded in c), is obtained;

e) register the amplitude and frequency of the supplied input phase jitter and repeat operations d) – e) with a number of frequencies sufficient to determine the characteristics of the permissible phase jitter.

Rice. 6.4 Scheme for measuring permissible phase jitter (method according to the Kosh increase criterion) 6.3.1.3. Error criterion method The error criterion for measuring the permissible value of phase jitter is defined as the largest amplitude of phase jitter at a given frequency, ultimately resulting in no more than two seconds with errors/summed in successive 30-second measurement intervals, during which the amplitude of the phase jitter trembling increased.

The method under consideration consists of adjusting the frequency of the jitter and determining the amplitude of the jitter of the test signal to ensure that the error criterion is met.

This method includes the following operations:

1) exclusion of the “transition region” of the amplitude of phase jitter (in which error-free operation stops);

2) measuring individual seconds with errors for 30 seconds for each increase in jitter amplitude, starting from the area specified in point 1);

3) determination of the greatest amplitude of phase jitter, at which the total number of seconds with errors does not exceed two.

The process is repeated for a sufficient number of frequencies that the measurement accurately reflects the sinusoidal input jitter acceptable to the test object over the required frequency range. The measuring device must produce a jitter-controlled signal and measure the number of error seconds due to jitter in the input signal.

In Fig. Figure 6.5 shows the measuring device used for the error criterion method. An optional frequency synthesizer provides a more precise definition of the frequencies used for measurements. An additional jitter receiver is used to monitor the amplitude of the generated jitter.

Operating procedure:

a) establish connections as shown in Fig. 6.5. Check the integrity and make sure that the measured object works without errors;

b) set the input jitter frequency to the desired value and adjust the amplitude of the phase jitter to 0 unit peak-to-peak intervals;

c) increase the jitter amplitude using coarse adjustment to determine the amplitude region in which error-free operation ceases. Reduce the amplitude of the jitter to the level at which this area begins;

d) record the number of seconds with errors noted during the 30-second measurement interval. Please note that the initial measurement must show no seconds with errors;

e) increase the amplitude of phase jitter using smooth adjustment, repeating operation d) until the error criterion is satisfied;

f) register the amplitude displayed by the measuring device and repeat operations b) – e) with a number of frequencies sufficient to determine the characteristics of permissible phase jitter.

Rice. 6.5 Scheme for measuring permissible phase jitter (method based on the error criterion) 6.3.1.4. Compliance of the permissible value of jitter with the template(s) The permissible value of jitter for a channel, path or equipment is determined using jitter tolerance patterns. Each pattern indicates an area in which the equipment must operate without degrading the normalized error rate. The difference between the pattern and the effective tolerance characteristic of the equipment shows the jitter margin. Testing for pattern compliance is accomplished by setting the jitter frequency and amplitude to the pattern value and by monitoring for the absence of a normalized error rate reduction.

The measurement is made with a sufficient number of pattern points to ensure compliance across the entire frequency range of the pattern.

The method of paragraph 6.3.1.2 or 6.3.1.3 and, accordingly, the diagram in Fig. 6.4 or 6.5.

Operating procedure:

a) install connections in the equipment according to the diagram in Fig. 6.4 or 6.5 (depending on the specific case). Check the integrity and make sure that the measured object works without errors;

b) set the amplitude and frequency of phase jitter according to one of the template points;

c) when using the method based on the error occurrence criterion, confirm the absence of seconds with errors. When using the method based on the K„ deterioration criterion, confirm that the normalized reduction in the error rate has not been achieved;

d) repeat the operations specified in paragraphs b) and c) over a sufficient number of pattern points to ensure compliance with the jitter tolerance pattern.

6.3.2. Measurement of output phase jitter (clauses 5.1, 5.3b and 5.4c Standards)

Output jitter measurements fall into two categories:

1) output phase jitter at typical junctions of channels and network paths;

2) intrinsic phase jitter generated by specific digital equipment.

Output jitter measurements may be expressed as effective peak-to-peak amplitudes over certain frequency ranges and may require statistical processing.

Output jitter measurements are performed using either the real load signal or driven test sequences.

6.3.2.1. Real Load Output jitter measurements at typical channel and path junctions are typically made using real load signals. Acceptance tests that use controlled test sequences are discussed in clause 6.3.2.2. The present method consists of demodulating the jitter of the actual load at the output of the network interface, selectively filtering the jitter, and measuring the true effective value or true sinusoidal value of the jitter amplitude in a certain time interval.

In Fig. Figure 6.6 shows a device used to measure a real load signal. An optional spectrum analyzer provides observation of the frequency spectrum of the output jitter.

Operating procedure:

a) install connections according to the diagram in Fig. 6.6. Check the integrity and make sure that the measured object works without errors;

6.3.2.2. Guided Test Sequences Measuring the inherent jitter of individual digital equipment requires the use of controlled test sequences. These sequences are commonly used in laboratory and plant environments and during decommissioning of the measured object. The basic method described below provides details on how to make these measurements.

If more complete information about the power of the output jitter (more precisely, the jitter produced in digital regenerators) is required, the jitter can be divided into random and systematic components. Distinguishing between random and systematic phase jitter is necessary mainly to ensure comparison of measurement results with theoretical calculations and to clarify the designed regenerator circuit. For this purpose, methods are used that are not discussed in this document.

The basic method for measuring intrinsic jitter is identical to the method described in clause 6.3.2.1, with the only difference being that a jitter-free controlled test sequence is applied to the equipment under test. The additional frequency synthesizer shown in Fig. 6.6, serves to more accurately determine the frequencies used in the measurement.

Operating procedure:

a) install connections according to the diagram in Fig. 6.6 using a digital signal generator to provide the equipment under test with a controlled, jitter-free test sequence. Check the integrity and make sure that the measured object works without errors;

b) choose required filter jitter measurements and measure the output jitter in a given frequency band by recording the true peak-to-peak amplitude value occurring over a specified time interval;

c) repeat the operation of point b) for all the necessary jitter measurement filters.

6.3.3. Measurement of the transfer characteristic of phase jitter (clause 5.3c of the Standards) Methods for measuring the transfer characteristic of phase jitter (clause 5.3c and

5.4b Standards) are subject to development.

– – –

6.4.1. General requirements 6.4.1.1. Power supply requirements The devices must be powered from an alternating current network with a frequency of (50 ± 2.5) Hz and a voltage of 220 (+22; -33) V with a harmonic content of up to 10%.

6.4.1.2. Operating conditions In terms of resistance to climatic and mechanical influences, devices must comply with the requirements of the 3rd group of GOST 22261.

6.4.2. Requirements for the input (output) of measuring instruments 6.4.2.1. The input and output impedance and mismatch attenuation of devices intended for measuring the parameters of digital channels and paths with communication interruption and connected to standardized joints of these channels and paths must correspond to the values specified in table. 6.1.

The asymmetry attenuation of the input of devices intended for measuring the bcc and the primary digital path must be at least 30 dB in the same frequency ranges.

6.4.2.2. The input impedance and attenuation of inconsistency of devices intended for measuring the parameters of digital channels and paths without interrupting communication and connected to channels 8 paths at protected measuring points (having decoupling devices) must also correspond to the values specified in table. 6.1. In this case, the devices must provide additional amplification of the input signal to compensate for the attenuation of decoupling devices at the measuring points (up to 30 dB).

Rice. 6.6 Output jitter measurement circuit (basic method) For objects to be measured where there are no protected measuring points, the instruments must be equipped with a high-resistance input impedance.

– – –

6.4.2.3. Devices at the input and output must ensure operation with signals in the form of pulses, standardized (amplitude and shape of pulses, codes, etc.) for the corresponding joints.

6.4.2.4. Devices must operate correctly (both in disconnected and non-disconnected mode) if they are connected to the output of the joints using a piece of cable with an insertion attenuation of 6 dB at a frequency corresponding to half the transmission rate of the measured path. The cable insertion loss at other frequencies is proportional to f.

6.4.3. Requirements for test signals 6.4.3.1. For measurements with communication interruption, devices must generate measurement signals in the form of pseudo-random pulse sequences that most fully simulate real signals and at the same time are known in advance. The latter is necessary to measure error rates.

The length of pseudo-random sequences (PRS) should be equal to (2n – 1) bits, where n depends on the transmission speed of the measured path (see Table 6.2). In addition to a group of n consecutive ZEROS (for the so-called inverted signal) and n – 1 consecutive ONEs, such sequences contain any possible combination of ZEROS and ONEs within the length of the group, depending on n.

– – –

The devices must provide the following PSP:

a) 2047-bit pseudo-random test sequence (designed to measure errors and jitter at 64 kbit/s and 64 x N kbit/s).

This sequence can be generated in an 11-link shift register, the outputs of the 9th and 11th links are summed modulo 2 in the summation link, and the result is fed back to the input of the first link.

Number of shift register units 11 Pseudo-random sequence length 211 – 1 = 2047 bits Longest sequence of zeros 10 (non-inverted signal).

Note. When performing measurements at baud rates N x 64 kbit/s, successive 8-bit blocks of the test sequence must be transmitted in consecutive time slots. The start of the pseudo-random sequence does not need to be related to the frame rate.

b) 32767-bit pseudo-random test sequence (designed to measure errors and jitter at transmission rates of 2048 and 8448 kbit/s).

This sequence can be generated in a 15-link shift register, the outputs of the 14th and 15th links are summed modulo 2 in the summation link, and the result is fed back to the input of the first link.

Number of shift register units 15,215 – 1 = 32,767 bits Pseudo-random sequence length Longest sequence of zeros 15 (inverted signal).

c) 8388607-bit pseudo-random test sequence (designed to measure errors and jitter at transmission rates of 34368 and 139264 kbit/s).

This sequence can be generated in a 23-link shift register, the outputs of the 18th and 23rd links are summed modulo 2 in the summation link, and the result is fed back to the input of the first link.

6.4.3.2. Additionally, to measure phase jitter the following must be provided:

a) two freely programmable 8-bit sequences that can be interleaved at low speed;

b) freely programmable 16-bit sequence.

6.4.3.3. To measure digital paths containing multiplexing equipment using a measurement signal, specific bit sequences must be applied to the input in order for them to function correctly during the measurement process. The measurement signal must contain at least a correct frame clock signal.

It must be possible to insert additional service information into the measuring signal.

There must be two cases of generating a measuring signal:

a) In general, measurements must be made through digital grouping equipment and a properly formed test signal is required. This signal must contain the appropriate frame clock word, stuffing (alignment) bits, and all required path header to ensure proper operation of the terminal equipment. Thus, the test signal must be generated as it would appear at the output of a properly operating digital multiplexer. This structure is shown in the following example.

One cycle Group 1 Group 2 Group 3 Group 4 FAS TS1, TS2, Сj1 TS1, TS2, Сj2 TS1, TS2, Сj3 TS1, TS2, TS3, TS4 TS3, TS4 TS3, TS4 TS3, TS4 where FAS = frame clock plus alarm bits alarms;

TSm = interleaved component test sequence bits 1 to 4;

Cjn = alignment control bits.

Note. Detailed information about the rules for generating measurement signals in the form of cycles depending on the grouping structure is given in Appendix 3. The bits of the test sequence are numbered sequentially there. This does not mean that these bits must belong to the same sequence. Depending on the application, it may be preferable to provide independent test sequences in groups representing lower order component signals.

b) in the second case, it is necessary to check the operation of only the input part of the path (grouping equipment). Examples of such tests are measurements of permissible input jitter, checking the frame timing signal, alarm condition indications, etc. This type of measurement does not require that the test signal contain the correct stuffing information, and it is not necessary to condition the input digital signal to a higher order such that meaningful digital signals appear at the outputs of the component paths. Such a signal is generated as shown below.

– – –

where FAS = frame clock plus alarm bits;

TS 1 to y = test sequence bits that can only belong to one sequence.

6.4.3.4. The rules for generating the measuring signal in the form of digital signal cycles must comply (see also Appendix 3).

6.4.4. Requirements for the transmitting part of measuring instruments 6.4.4.1. Synchronization Requirements

The transmitting part - the measuring signal generator (hereinafter - GIS) must operate:

from its own clock generator at frequency f of the measured digital signal with an error of no more than ±1.5 · 10–5 · f kHz with the possibility of a shift by ±1.5 · 10–5 · f ±1 · 10–4 · f;

from an external clock signal with a frequency error of no more than ±50 · 10–6 · f and an amplitude of 50 mV – 1 V;

from the clock signal (clock + octet) extracted from the received signal (when measuring the main digital channel).

If the device is designed to measure the main digital channel (BCC), in the mode of the counter-directional joint of the BCC, two operating options should be provided in the GIS:

I – as a consumer (towards 64/2048 kbit/s conversion equipment), synchronization – from the synchronizing signal of the opposite directional junction (clock + octet);

II – as conversion equipment (towards the 64 kbit/s line), synchronization – from its own and from an external clock generator; supply of a synchronizing signal (clock + octet) to the 64 kbit/s line.

6.4.4.2. For GIS intended for measuring error rates, it must be possible to introduce calibrated errors into the measuring signal within the error coefficient from 10–8 to 10–3, as well as errors into the cyclic synchronization signal from 10–6 to 10–2. Single errors must also be introduced errors at the operator’s command, as well as (preferably) error packets.

6.4.4.3. For GIS intended for measuring the permissible value and transfer characteristic of phase jitter, it must be possible to introduce phase jitter into the measurement signal in accordance with the requirements of ITU-T O.171 for the amplitude of the generated phase jitter.

The intrinsic phase jitter in the GIS output signal should be no more than 0.01 UI (unit intervals).

The modulation source can be external or included in the device.

6.4.5. Requirements for error indicator meters 6.4.5.1. The error meter (hereinafter referred to as EO) must work with an internal highlighter clock frequency from the received signal, as well as from an external clock signal with a frequency error of up to 100 10–5 f. In the mode of the counter-directional interface of the bcc, operation should be carried out from the synchronizing signal (clock + octet) for option I of switching on the device (see clause 6.4.3.1). In option II, a synchronizing signal output (clock + octet) must be provided.

6.4.5.2. An EUT intended for measuring error rates with communication interruption must identify errors using the character-by-character comparison method in test sequences according to paragraphs. 6.4.3.1 and 6.4.3.2 in digital signals of channels and paths, as well as (if the device is designed for this) in “n” channel intervals selected by the operator from channel intervals 01 – 31 of the primary digital stream.

6.4.5.3. An EUT designed to measure error rates without interruption of communication or with termination of communication using a test signal formed in the form of a cycle (see clause 6.4.3.3) must also determine errors in the cycle synchronization signal extracted from the digital signal and, if it is intended for measuring PCT , in the CRC-4 word (in accordance with ITU-T Recommendation G.704).

6.4.5.4. The EO must provide:

error rate measurement;

error count;

determination of error rates over a specified period in accordance with ITU-T Recommendation M.2100 (see Appendix 4);

determination of error rates over a specified period in accordance with ITU-T Recommendation G.826 (see Appendix 4). When analyzing errors by block, the block size values for various paths should comply with Recommendation O.150.

– – –

Note. The block size value is based on a multiple of 125 µs. The actual block size/length may differ from the nominal value given in the table by ±5%.

It is also desirable to provide a count of the number of slips (octet and bit).

The listed error indicators must be calculated within the availability time (see Appendix 4), and periods of unavailability must also be recorded.

6.4.5.5. The error rate measurement range should be in accordance with ITU-T Recs O.151 and O.152, at least from 10–3 to 10–8 for bit rates of 2048 kbit/s and above and from 10–2 to 10– 7 for 64 kbit/s speed.

6.4.5.6. The period for measuring error indicators should be set within the range of no less than 1 minute to 1 month. A start-stop operating mode must also be provided.

6.4.5.7. The IE, in accordance with its purpose (with or without termination of communication, path type), must provide for the indication of defects and anomalies in accordance with ITU-T Recommendation M.2100 (see Appendix 4) and take them into account when processing measurement results to obtain error indicators per measurement session.

6.4.6. Requirements for the phase jitter meter 6.4.6.1. Requirements for the jitter meter in terms of measurement limits and measurement accuracy, filter characteristics, the maximum measured value of the jitter peak-to-peak depending on the frequency and transmission rate of the digital signal, the bandwidth of the jitter measurement circuit and filters must comply with Recommendation ITU-T O.171.

6.4.6.2. The reference timing signal for the phase detector can be obtained using a clock extractor from the received signal (see section 6.4.5.1) or from the internal clock generator of the transmitting part of the device.

6.4.6.3. The total measurement error at a jitter frequency of 1 kHz (excluding the error due to the frequency response) must be less than ±5% of the reading ±X ±Y, where X is the systematic error, depending on the type of test signal, and Y is the error, the value of which is equal to 0.01 of the peak-to-peak value in UI (0.002 of the rms value) and which appears if internal clock allocation is used (For the value of X, see Recommendation O.171).

6.4.6.4. The additional frequency jitter measurement uncertainty shall be in accordance with Recommendation O.171.

LITERATURE FOR SECTION 6

3. ITU-T Recommendation G.751. Digital multiplexing equipment operating at a third-order bit rate of 34368 kbit/s and a fourth-order bit rate of 139264 kbit/s and using positive digital equalization.

Issue III.4, Blue Book, 1988.

Revised 1995

9. GOST 26886–86. Joints of digital transmission channels and group paths of the primary EACC network. Main parameters.

10. GOST 27763–88. Structures of cycles of digital group signals of the primary network of a unified automated communication network. Requirements and standards.

11. GOST 5237–83. Telecommunication equipment. Supply voltages and measurement methods.

12. GOST 22261–82. Instruments for measuring electrical and magnetic quantities. General technical conditions.

ANNEX 1

– – –

For systems such as IKM-480R, PCM-480S, IKM-480 used on the existing primary network, the standards are established at the level of requirements for systems used on the VZPS.

In this case, the calculation of standards in the case of using the system on the NSR should be carried out with the following amendments:

– – –

To determine operational standards in accordance with paragraph.

4.2.7 of these Standards, the calculation of the value of D for a simple path or each section of a composite path is carried out taking into account the Mop coefficient:

D = DT x Mop, Where DT is the table value for a path of a certain length, found from the table. 4.4, Mop is a coefficient that takes into account the degree of weakening of the operational norm for the old DSP, while, when applying it on the NSR, this coefficient is proposed to be set equal to Md = 6.3, when applied to the VZPS - Mop = 1.

APPENDIX 3

In table 1 P3, 2.1 P3 and 2.2 P3 show domestic and foreign devices, respectively, currently produced and intended for measuring BCC and digital network paths. The tables indicate the capabilities of measuring instruments, their dimensions and price.

The table shows that long-term standards, based on ITU-T recommendation G.826, allow measuring only the most modern devices from foreign companies, usually intended for synchronous digital hierarchy (the latter is not reflected in the table).

Very few instruments produce results in accordance with the criteria of ITU-T Rec. M.2100 (see Annex 4), although the corresponding anomalies and defects are usually recorded, but they are not always taken into account when calculating ES and SES. In most of the instruments used, the results are analyzed in accordance with Annex D of ITU-T Recommendation G.821, i.e. reduced to a transmission speed of 64 kbit/s. Recommendation M.2100 allows the use of such instruments; the resulting error is usually not very significant, especially for fairly long-term measurements.

It should also be noted that none of the domestic devices fully meets the necessary requirements. The IKO-S and IKOFD devices (after the modernization - IKOFD-M, placed in one package instead of three) can still be used to evaluate paths for compliance with standards, because they allow error performance to be measured in accordance with Annex D of ITU-T Rec. G.821.

The table shows data from the IKO-1 and PPRPT-4(34) devices, which are somewhat widespread in communication networks, which allow you to measure only the error rate and are intended for setting up digital transmission systems and repairing regenerators and other units. The normalized parameters of error indicators cannot be assessed with their help, therefore these devices can be used only temporarily for an approximate assessment of the quality of paths until the necessary equipment is purchased.

Tables 2.1 P3 and 2.2 P3 include devices from leading foreign companies in this area: Hewlett-Packard (HP), Siemens, Wandel & Goltermann (W&G), Schlumberger (Schlum), Marconi. The most typical of currently produced devices have been selected, but the range of devices in this group for most companies is much wider, the given devices are produced in various configurations, which should be taken into account when purchasing.

The choice of devices should be based on the capabilities given in the list; technical characteristics set out in the documentation for the devices; purpose (type of measurements in which the device is supposed to be used) and types of paths to be measured.

Table 1 P3 Domestic measuring instruments for digital channels and paths

– – –

APPENDIX 4

PARAMETERS USED FOR ASSESSMENT

COMPLIANCE WITH OPERATIONAL REGULATIONS

– – –

1) Anomalies

Non-defective anomaly states are used to determine path error rates when the path is not in a defective state. The following two categories of anomalies related to the incoming signal are defined:

a1 – cyclic synchronization signal with errors;

a2 – error block (EB), detected using built-in control methods (cyclic redundancy check, parity check) – not applicable for paths of types 2 and 3 (see below).

2) Defects

Non-defective defect states are used to detect a change in performance status that may occur in a path. The following three categories of defects related to the incoming signal are defined:

d1 – signal loss;

d2 – SIAS emergency condition indication signal d3 – loss of frame synchronization (LOF).

The criteria for the occurrence of a defect condition must correspond to the specific equipment. For equipment at different levels of the hierarchy, definitions of criteria for the LOS and AIS defect states are given in ITU-T Rec. G.775, and for the LOF defect also in the G.730 to G.750 series of Recommendations.

3) Formation of error indicators depending on the type of path In Table. 1 P4 provides the rules by which the values of error indicators should be formed, based on the registered anomalies and defects, for the types of paths available on the VSS.

Depending on the type of monitoring means without interruption of communication (IC) available in the path formation equipment, it may not be possible to obtain the entire set of parameters of quality indicators.

Three types of paths can be defined for BSS:

Type 1: Path with a cyclic and block structure. The entire set of defects from d1 to d3 and anomalies a1 and a2 are determined using IC tools. Examples of this type of path are: primary and secondary paths with CRC (4 to 6) in accordance with ITU-T Rec. G.704; quaternary paths with a parity bit on each frame in accordance with ITU-T Rec. G.755.

Type 2: Paths with a cyclic structure The entire set of defects from d1 to d3 and anomalies a1 are determined using IC tools. Examples of this type of path are typical network paths from primary to quaternary in accordance with GOST 27763-88.

Type 3: Paths without cycles It is possible to determine, using VC tools, the limitations of the set of defects d1 and d2, which do not include checking for any error. There is no frame sync (FAS) control.

An example of this type of path would be a digital channel provided to a consumer, formed in several higher order paths connected in series.

– – –

Notes:

1) If more than one anomaly a1 or a2 occurs during the interval of one block, one anomaly shall be counted.

2) The “x” values for paths of different orders are indicated in table. normal

3) The ESR and SESR estimates must be identical, since the SES event is part of the ES event population.

a) Error rates normalized for a 64 kbit/s digital connection. Errored Second (ES) A one-second period with one or more errors.

Error-Stricken Second (SES) A one-second period of average bit error rate in which 10–3.

SES is included in the ES population.

Note: Both ES and SES are recorded during the ready time (see paragraph 1 of these standards).

6) Error rates normalized for digital systems with bit rates above 64 kbit/s (Annex D of Recommendation G.821, repealed by Recommendation G.826) Errored Second (ES) Number of errored seconds normalized to 64 kbit/s /With. The percentage of seconds with errors is determined by the formula:

1 i= j n 100% j i=1 N where n is the number of errors in the i-th second at the measurement speed;

N – measurement speed divided by 64 kbit/s;

j is an integer number of one-second intervals (excluding unavailability time) during the entire measurement time;

ratio (n/N), for the i-th second is equal to:

n/N, if 0 n N, or 1, if n N.

Errored Second (SES) Errored seconds include, in addition to one-second intervals with an average bit error rate of 10–3, one-second intervals in which a loss of frame synchronization is recorded.

a) Error performance parameters (ES/SES) during evaluation without interruption of communication

1) Anomalies:

FAS with errors - binary errors in any bit/word of the frame clock signal during a 1-second interval;

E-bits – CRC-4 block indication bits with reverse direction errors;

controlled slips.

2) Defects:

LOF – loss of frame synchronization;

LOS – signal loss;

bit errors in the frame clock signal. If the hardware can detect binary errors in the FAS word, then SES can be detected using the specified value. If the equipment can only detect a violation of a FAS word, then the same number of violated FAS words results in an SES;

A-bits – far-end alarm status indication (AIS);

Far-end defect indication RDI bits.

3) Formation of error indicators based on information about anomalies and defects without interrupting communication, depending on the type of path.

Error indicator values are generated based on an analysis of recorded anomalies and defects for a 1-second interval. In the case of an anomaly, as a rule, ES is recorded, in the case of a defect, ES and SES. The evaluation criteria for ES and SES depend on the type of path and the equipment used to create it (ie, the use of bits 1–8 for monitoring purposes).

In table 2 P4 provides criteria for assessing without interrupting communication for various paths used on the VSS.

b) Error indicator parameters (ES/SES) during evaluation (measurements) with communication interruption. Parameters ES and SES are estimated based on anomalies and defects with communication interruption received from measuring instruments for the corresponding integration period.

1) Anomalies The basis of an anomaly is an error in a unit interval (bit).

When using a measurement signal formed in the form of a cycle, it is possible to evaluate some “anomalies without interrupting communication” (see paragraph 3a).

2) Defects

Loss of sequence synchronization, which occurs when:

burst of intense errors of long duration, AIS of long duration, uncontrolled bit slipping, signal loss.

When using a measuring signal formed in the form of a cycle, it is possible to evaluate some “defects without interrupting communication” (see paragraph 3a).

3) Formation of error indicators in measuring instruments. Since measurement instruments usually have bit resolution, the main evaluation criterion for the ES and SES parameters should be:

ES – 1 second period with 1 bit errors;

SES is a 1 second period with an average BER (KObit) of 10–3.

Note: Both ES and SES are recorded during the ready time.

Table 2 P4

– – –

Note. The number of RDI bits per second as a defect criterion in ITU-T is being studied.

In addition, if the measuring instruments use a measuring signal in the form of a PSP, which is inserted into a standardized path signal, you can also use an additional evaluation criterion ES/SES in accordance with information without stopping communication on anomalies and defects in accordance with clause 4.1.3. However, if the measuring instruments use a measuring signal that is not formed in the form of a cycle, i.e.

it is not inserted into the standardized signal path, then the only additional information about anomalies and defects that can be taken into account is:

anomalies – violations of the interface code (in accordance with Recommendation G.703);

defects – AIS, LOS.

In particular, a 1-second period with 1 LOS is considered to be SES (and ES).

Note: It is believed that AIS may actually cause BER for 0.5 of its duration. If an AIS is of sufficient duration to cause a BER of 10–3 in any 1-second period, it can be considered an event when evaluating SES (+ES) parameters. However, a signal with all bits except the frame clock at 1 shall not be mistaken for AIS.

1. Terms and definitions

2. General provisions

3. General characteristics of digital channels and paths

4. Standards for error rates of digital channels and network paths

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"Standardization of electrical characteristics of cable lines"

1. Electrical standards for main and zone cable lines

1.1 Electrical standards on the PRC line

At present, many transmission systems with frequency division of channels such as K-60 and KAMA are still in operation on the lines of the main and zonal networks of the Russian Armed Forces.

For the nominal lengths of amplifying sections with permissible deviations from them adopted for various transmission systems, standards have been established for the electrical parameters of symmetrical HF DC cables.

Table 1. Standards for electrical parameters of symmetrical RF cables running on direct current

Parameter
Electrical insulation resistance between each core and the other cores connected to a grounded metal shell (screen) at a temperature of +20 °C, MΩm, not less
Electrical insulation resistance of any polyethylene protective hose cable cover, MOhm, not less
Electrical insulation resistance of the polyvinyl chloride hose cover of the cable 1x4x1.2 between the screen and the ground, MΩm, not less
Electrical resistance of a circuit (loop of cores) with a diameter of 1.2 mm of a working pair at a temperature of +20 °C, MOhm, not less
Difference in electrical resistance of cores with a diameter of 1.2 (asymmetry) in a working pair of HF cables, no more
Test voltage of HF cables, V: between all the cores of the quads connected into a bundle and a grounded metal shell (screen) between each core and the other cores of the quads, connected in a bundle, and with a grounded metal sheath
Note: 1. If there is air (nitrogen) pressure in the cable, the test voltage increases by 60 V for every 0.01 MPa. 2. For cables laid in high mountain areas, the test voltage standard is reduced by 30 V for every 500 m of altitude. 3. / - length of the reinforcement section, km.

The norms for the influence parameters of circuits of symmetrical cables equipped with K-60 and KAMA equipment are given in Tables 2 and 3, respectively.

Table 2. Norms of influence parameters of K-60 circuits

Parameter		Norm, dB
	combinations
Distribution of transient attenuation values at the near end, not less than: 4x4 capacity cable Cable capacity 7x4 Cable capacity 1x4
Distribution of circuit protection values at the far end, not less than: 4x4 capacity cable Cable capacity 7x4 Cable capacity 1 x4
Note: When determining the actual distribution of the values of transient attenuation and protection between circuits in a 1x4 cable for 100% of the combination, the number of combinations of mutual influence in sections of one transmission direction in the OUP-OUP section is used.

Table 3. Norms of influence parameters of KAMA circuits

In accordance with the requirements set out in Tables 2 and 3, the lowest value of the frequency characteristics of the coupling attenuation at the near end and the security at the far end of a given combination of mutually influencing pairs is measured. The frequency characteristics of the influence parameters are measured with a VIZ-600 or IKS-600 device in the frequency range of 12-250 kHz for K-60 transmission systems and in the range of 12-550 kHz for KAMA equipment. Normalization by the smallest value of the frequency response of the influence is associated with the features of analog transmission systems with amplitude modulation and frequency division of channels. With amplitude modulation, the effectively transmitted frequency band of one PM channel is 0.3...3.4 kHz. Therefore, narrow-band dips in the characteristics of influences can significantly increase the transitional conversation in any channel.

When organizing a two-cable transmission system, the required value of the transition attenuation at the near end of the amplifying section between circuits of opposite transmission directions is determined by the formula:

where A)0 = 55 dB is the security of a transitional conversation between different transmission directions of the same PM channel, a/wx = 54.7 dB is the maximum permissible attenuation of the amplifying section, L = 2500 km is the length of the nominal section.

In accordance with these lengths, A02 ^ 55 + 54.7 + 21.4 = 131.1 dB.

Taking into account the fact that the energy transition from a high level point (amplifier output) to a low level point (amplifier input) is also carried out through inter-rack distribution cables, the recommended minimum value of the transition attenuation between the main cable circuits of opposite transmission directions is taken to be 140 dB.

1.2 Electrical standards on the DSP line

In modern digital transmission systems (DTS), used on trunk and zonal communication lines, the main type of analog-to-digital conversion is the receipt of a PCM signal from a message transmitted over a standard PM channel with an effective frequency band from 0.3 to 3.4 kHz.

For this case, it is optimal from the point of view of minimizing equipment costs at acceptable level quantization noise are the following parameters of analog-to-digital conversion: the upper frequency of the Fourier spectrum of analog signals transmitted over the HF channel f e = 4 kHz; cycle duration of the AIM signal DF = 125 μs. At these parameters, the Fourier spectrum of the AF MKM PCM signal extends to 64 kHz. This frequency range is obtained from the relation AF MKM = 2f e n, where n-2 is the Kotelnikov coefficient.

The peculiarity of the PCM signal predetermines the structure of multi-channel DSPs as systems with time division of channels. In this case, systems of other channels are transmitted in a free time period.

Currently, DSPs form a set of systems (hierarchy) with mutually agreed upon transmission speeds: Primary, Secondary, Tertiary and Quaternary transmission systems.

The main technical characteristics of the DSP are given in Table 4.

Table 4. Technical characteristics of the DSP

Transmission system	Transfer rate, kbit/s	Clock frequency, MHz	Half-clock frequency, MHz	Clock interval,	Elementary pulse width, not	Number of channels
Primary (PCSP)
Secondary (VCSP)
Tertiary (TCSP)
Quaternary (CCSP)

The lines from the MKS and ZKP cables are currently sealed with secondary DSPs.

OST 45.07-77 "Electrical standards for mounted amplification sections of a secondary digital transmission system" determines the conditions for the use of trunk lines for PCM-120 equipment. "

The main element of the digital path is the regeneration section. The lengths of the regeneration sections for which the electrical characteristics are standardized are given in Table 5.

Table 5. Lengths of regeneration sections

The nominal length of the regeneration section is determined by the nominal gain of the correction amplifier (55 dB) and the nominal attenuation of a given type of cable at half-clock frequency (4224 kHz), and the largest and smallest - by the limits of the AGC and the temperature and permissible attenuation variations of the cables. Electrical standards for alternating current in the frequency range 20-550 kHz, applied to cable pairs equipped with VTsSP equipment: protection between circuits at the far end - not less than 52 dB; The near-field attenuation is less than 48 dB.

1.3 New standard for electrical characteristics - trunk and zone cable lines

In 1998, instead of the standard 45.01.86, a new revised OST 45.01-98 was introduced: "PRIMARY NETWORK OF THE INTERCONNECTED COMMUNICATION NETWORK OF THE RUSSIAN FEDERATION. Elementary cable sections and sections of cable transmission lines. Electrical standards." Let us comment on the main provisions of this document.

Application area:

The OST 45.01-98 standard applies to elementary cable sections (ECU) and cable sections (CS) of transmission lines of the main and intra-zonal primary networks of the Russian Armed Forces. The standard sets standards for the electrical parameters of direct and alternating current circuits mounted by ECU and CS analog and digital transmission systems.

The standard adopts the following definitions:

Transmission line is a set of physical circuits and (or) linear paths of transmission systems that have common linear structures, devices for their maintenance, as well as a propagation medium (GOST 22348).

Elementary cable section (ECU) - a section of a cable line together with mounted cable terminal devices.

A cable section (CS) is a set of electrical circuits connected in series at several adjacent ECUs for several transmission systems with equal distances between regenerators (amplifiers), but with a distance greater than the length of the ECU of a given line.

Regeneration section - a combination of an ECU or CS circuit with an adjacent regenerator.

OST 45.01-98 applies to ECU and KS, consisting of: - coaxial cables with pairs having washer, balloon or porous polyethylene insulation (cable types KM-4, KMA-4, KME-4, KM-8/6, MKT -4, MKTA-4 and VKPAP);

from symmetrical HF cables with cord-polystyrene or polyethylene insulation (cables of types MKS, MKSA, MKST, ZKP).

Coaxial and symmetrical HF cable transmission lines can be used for analog and digital systems for various ranges of transmitted frequencies and various transmission speeds (Tables 6, 7)

Table 6. Transmission systems via coaxial communication cables

Transmission system		Coaxial pair type

		1,2/4,6 (1,2/4,4)

		2,6/9,4 (2,6/9,5)

		2,6/9,4 (2,6/9,5)



		1,2/4,6 (1,2/4,4)

IKM-480 (LS34CX)	34.368 Mbps
	51.480 Mbps
	139.264 Mbps	2,6/9,7 (2,6/9,5)

Table 7. Transmission systems over coaxial and symmetrical communication cables

Transmission system	Frequency range - transmission speed




IKM-120 (IKM-120A, IKM-120U)	8448 kbps
IKM-480 (LS34S)	34368 kbps
Note: the designation K-60 should be understood as transmission systems: K-60, K-60P, K-60P-4M, V-60, V-60S, V-60F

2. Electrical standards for local communication lines

2.1 General provisions

The electrical characteristics of the installed local communication cable lines must meet the requirements given in industry standards:

OST 45.82-96. City telephone network. Subscriber cable lines with metal conductors. Operational standards. OST 45.83-96. Rural telephone network. Subscriber cable lines with metal conductors. Operational standards. OSTs came into force on January 1, 1998.

The standards apply to subscriber cable lines with metal cores of city telephone networks (AL GTS): electronic digital telephone exchanges; quasi-electronic telephone exchanges; coordinated automatic telephone exchanges; decade-step automatic telephone exchanges.

The standard establishes standards for the electrical parameters of AL GTS, STS circuits and their elements that ensure the functioning of:

1) telephone communication systems;

2) telegraph communication systems, including public telegraph services, subscriber telegraph, telex;

3) telematic services, including fax services, video text, e-mail, message processing;

4) data transmission systems;

5) systems for distribution of sound broadcasting programs;

6) digital systems with service integration.

The requirements of the standards must be taken into account during the operation, design, construction of new and reconstruction of existing lines of city telephone networks, as well as during certification tests.

2.2 Electrical standards for GTS cable lines

The structure of AL GTS electronic (EATS-90, MT-20), coordinate (ATSK, ATSKU) and ten-step (ATS-49, ATS-54) stations includes: main section; distribution area; subscriber wiring.

On AL GTS, cables of the TPP type with copper conductors with a diameter of 0.32 are used; 0.4 and 0.5; 0.64; 0.7 mm with polyethylene insulation and in a polyethylene sheath and TG type cables with copper conductors with a diameter of 0.4 and 0.5 mm with paper insulation and in a lead sheath.

For subscriber wiring, wires are used - single-pair telephone distribution wires with copper conductors with a diameter of 0.4 and 0.5 mm with polyethylene and polyvinyl chloride insulation, respectively.

Connections in cross-connections and distribution cabinets are made using cross-connecting wires of the PKSV brand with a copper core diameter of 0.4 and 0.5 mm.

Digital subscriber lines include:

lines connecting electronic telephone exchanges with group subscriber installations (digital concentrators, multiplexers);

lines connecting electronic telephone exchanges with digital subscriber installations;

lines connecting group subscriber installations with terminal digital subscriber installations;

lines made of cable type TPP with a core diameter of 0.4; 0.5 and 0.64 mm with a two-cable communication scheme;

lines of cables for digital transmission systems of the TPPZTs type with core diameters of 0.4 and 0.5 mm and TPPep-2E type with a core diameter of 0.64 mm with a single-cable communication arrangement.

At the ALC, cables of the TPP type are used for the section from the group subscriber installation to the distribution center. For subscriber wiring, specialized cables are used.

Electrical standards for subscriber lines of city telephone networks

The electrical resistance of 1 km of subscriber cable line circuits to direct current at an ambient temperature of 20 °C, depending on the cable used, is given in Table 8.

The value of the asymmetry of the resistance of the AL GTS cores to direct current should be no more than 0.5% of the circuit resistance.

Table 8. Electrical resistance of subscriber cable networks

Cable brand for AL GTS	Core diameter, mm	Electrical resistance of 1 km of circuit, Ohm, no more
TPP, TGSep, TPPZ, TPPZep, TPPB	0,32 0,40 0,50 0,64 0,70	458,0 296,0 192,0 116,0 96,0
TPPepB, TPPZB, TPPBG,
TPPepBG, TPPbbShp, TPPepBbEp,
TPPZBbShp, TPPZepBbShp, TPPt


TPV, TPZBG



TG, TB, TBG, TK

TStShp, TAShp

The electrical insulation resistance of 1 km of AL GTS cores under normal climatic conditions, depending on the cable brand, must meet the requirements given in table.

Table 9. Electrical insulation resistance of 1 km of AL GTS cores

Cable brand for AL GTS	Electrical insulation resistance of 1 km of cores, MOhm, not less
	Line service life
	commissioning*
TPP, TPPep, TPPB, TPPepB, TPPBG, TPPepBG, TPPBbShp,
TPPZ, TPPZB, TPPZepB
TG, TB, TBG, TC for cores with insulation: tubular-paper, porous-paper

The attenuation value of the AL GTS circuits at a frequency of 1000 Hz should be no more than:

6.0 dB - for cables with core diameters of 0.4 and 0.5; 0.64 mm;

5.0 dB - for cables with a core diameter of 0.32 mm.

The value of the transition attenuation between the AL GTS circuits at the near end at a frequency of 1000 Hz must be at least 69.5 dB.

Standards for grounding resistance:

4 values of grounding resistance of metal screens and cable sheaths depending on soil resistivity are given in Table 10.

Table 10. Standards for grounding resistance

Electrical standards for lines of rural telecommunication networks:

Electrical standards for STS lines made of single-quadruple communication cables.

Electrical resistance of 1 km of STS circuit DC at a temperature of 20 °C, depending on the brand of cable used, is given in Table 11. The value of the asymmetry of the resistance of the DC cores of the cable STS circuit should be no more than 0.5% of the circuit resistance. The working electrical capacity of 1 km of circuit should be no more than:

35 nF - for KSPZP 1x4x0.64;:

3 8 nF - for KSPZP (KSPP) 1 x4x0.64.

Table 11. Electrical resistance of the STS circuit

The electrical insulation resistance of 1 km of AL STS cable cores, depending on the cable brand and service life, is given in Table 12. The electrical resistance of the insulation (sheath, hose) of 1 km of plastic cable shield relative to the ground during the entire service life must be at least 1.0 MOhm.

Table 12. Electrical insulation resistance of 1 km of AL STS cable cores

Electrical standards for rural digital subscriber lines.

STS ALCs are built using small-channel digital equipment, consisting of a multiplexer, a concentrator and xDSL equipment. For ALC, chains of existing lines from TPP cables can be used with pair selection based on transient attenuation at the near end. ALCs using a concentrator can be built using cables of the KSPZP 1x4x0.64 types; KSPZP 1x4x0.9 and low-pair cables KTPZShp 3x2x0.64 and 5x2 x0.64.

At the ALC, 30-channel digital transmission systems (multiplexers) can be used, operating via cable circuits KSPZP 1 x4x0.9 in a single-cable version. The use of digital thirty-channel transmission systems on existing AL cables from Chamber of Commerce and Industry using a single-cable communication scheme is not allowed. At the subscriber site from the concentrator (multiplexer) to the telephone set, lines of single-pair PRPPM cables, as well as subscriber wiring wires of the TRP and TRV types, are used.

Electrical characteristics of ALC (AL digital) STS from low-pair cables KTPZShp.

The parameters of the ALC STS from multi-pair cables running on direct current must meet the requirements given above.

The transition attenuation between circuits at the near end (Ao) of lines from multi-pair cables used for digital transmission systems of subscriber multiplexing and digital hubs in a single-cable version, at a half-clock transmission frequency or a pseudo-random sequence (PSR) signal, is determined by the formula:

where: N is the number of working DSP systems; b - attenuation coefficient at half-clock frequency of DSP signal transmission; / - length of the line used by the DSP; 24.7 - security value in dB, taking into account the required signal-to-noise ratio and system stability margin.

Parameters of AL STS circuits made of single-pair cables.

The electrical resistance of 1 km of DC line circuits at a temperature of 20 °C of a line mounted from PRPPM cables should be no more than: 56.8 Ohms - for cables with cores with a diameter of 0.9 mm; 31.6 Ohm - for cables with cores with a diameter of 1.2 mm.

The electrical insulation resistance of 1 km of PRPPM cable cores must be no less than:

75 MOhm - for lines in operation from 1 to 5 years; 10 MOhm - for lines that have been in operation for over 10 years.

The transition attenuation between circuits of parallel lines laid from single-pair PRPPM cables at the near end at a frequency of 1000 Hz must be at least 69.5 dB.

Standards for grounding resistance.

The values of the grounding resistance of metal screens and cable sheaths depending on the soil resistivity are given in Table 13, the value of the grounding resistance of cable boxes depending on the soil resistance - in Table 14, the values of the grounding resistance of subscriber protective devices depending on the soil resistivity - in table 15.

Table 13. Values of grounding resistance of metal screens and cable sheaths

Table 14. Value of grounding resistance of cable boxes

Table 15. Values of grounding resistance of subscriber protective devices

4. Standards for electrical parameters of PV networks

4.1 Parameters of low-frequency networks of single-program wire broadcasting

The quality indicators of radio broadcasting paths are established by the state standard. For rural PV networks, quality class II is provided. The qualitative indicators of the PV tract are given in Table 16.

Depending on the rated voltage, PV lines can be of two classes: Class I - feeder lines with a rated voltage over 340 V; Class II - feeder lines with a rated voltage of up to 340 V and subscriber lines with a voltage of 15 and 30 V.

The nominal voltage is the effective voltage of a sinusoidal signal with a frequency of 1000 Hz, at which the typical operating mode of the device is ensured. For newly designed and reconstructed radio broadcasting units, the following typical rated voltages are established: on subscriber circuits 30 V; on overhead distribution feeders 120, 240, 340, 480, 680 and 960 V; on underground distribution feeders 60, 85, 120, 170, 240 and 340 V; on overhead and underground main feeders 480, 680 and 960 V.

For each long feeder (distribution and main), the typical voltage rating depends on the length and load of the feeder. In this case, the voltage should be as minimal as possible so that the voltage attenuation in the line does not exceed the permissible value.

One of the main parameters characterizing the linear path of the PV network is its operating attenuation at a frequency of 1000 Hz. For wired broadcast networks built using

Table 16. Parameters of wired broadcast network paths

	Nominal range frequencies, Hz	Permissible deviations of frequency response, dB, or more	Harmonic coefficient,%, no more, at frequencies, Hz	Security, DB

I quality class:
Input TSSPV (SPV) - subscriber socket
Input TSSPV (SPV) -
linear path input
SPV (OUS) input -
subscriber socket
II quality class:
Input TSSPV (SPV) -
subscriber socket
Input TSSPV (SPV) -
linear path input
SPV (OUS) input -
subscriber socket

Note: Frequency bands for determining the permissible deviation of the frequency response in Class I paths for AS] 50-70 and 7000-1000 Hz; Class II for AS, 100-140 and 5000-6300 Hz; for AS 2 200-4000 Hz. _

According to the urban principle, the total operating voltage attenuation of three-element and two-element networks at the specified frequency at maximum permissible loads should not exceed 4 dB. In this case, the voltage attenuation over individual links is distributed as follows: for a subscriber line connected to the first half of the Russian Federation, up to 2 dB; for a subscriber line connected to the second half of the Russian Federation, 1-2 dB; for home networks up to 1 dB; for RF 2-3 dB; for MF up to 2 dB (it must be compensated by reducing the transformation ratio of the feeder step-down transformer at the transformer substation).

Uncompensated attenuation in the MF of up to 1 dB is also allowed. In this case, the total attenuation in the remaining sections of the RF and AL path (or home network) should not exceed 3 dB.

The attenuation of the PV path with long lines is distributed as follows. The attenuation of the subscriber line in a single-link network should not exceed 4 dB. An attenuation of 1-2 dB should be provided for the share of each subscriber line furthest from the PV station in a two-tier or three-tier network. The attenuation of underground unpupinized RF does not exceed 3 and 6 dB, depending on the type of cable and the length of the line. The attenuation of underground pupinized RF is determined at the rate of 3 dB per 5 km of line length. The permissible attenuation of the MF is 1 or 3 dB depending on the material of the wires (cores) of the line.

For the TVV network, the attenuation of subscriber and home networks is normalized at a frequency of 120 kHz. The attenuation of subscriber lines, depending on their length, should not exceed 3 dB for lines up to 0.3 km, 5 dB up to 0.6 km and 10 dB over 0.6 km.

Standards for communication channels. Operational standards for electrical parameters of switched channels of the PSTN network. General terms and definitions

LIST OF ABBREVIATIONS, CONVENTIONS, CHARACTERS

1. TERMS AND DEFINITIONS

1.1. General terms and definitions

1.2. Definitions of error rates for BCC

1.3. Definitions of error rates for network paths

2. GENERAL PROVISIONS

3. GENERAL CHARACTERISTICS OF DIGITAL CHANNELS AND TRACTS

4. STANDARDS FOR ERROR RATES DIGITAL CHANNELS AND NETWORK TRACTS

4.1. Long-term standards for error rates

ESR

4.2. Operational standards for error rates

5. STANDARDS FOR PHASE JITTER INDICATORS AND PHASE DRIFT

5.1. Network limit standards for phase jitter at the output of the path

1. GENERAL PROVISIONS

2. OPERATING STANDARDS FOR ELECTRICAL PARAMETERS OF SWITCHED CHANNELS OF THE PSTN NETWORK

GENERAL INSTRUCTIONS

2. OPERATING STANDARDS FOR ELECTRICAL PARAMETERS OF CHANNELS OF THE TF SWITCHED NETWORK (II EDITION)

“Ministry of Communications of the Russian Federation STANDARDS for the electrical parameters of digital channels and paths of backbone and intra-zonal primary networks The standards were developed by TsNIIS with the participation of...”

MINISTRY OF COMMUNICATIONS OF THE RUSSIAN FEDERATION

LIST OF ABBREVIATIONS, CONVENTIONS, SYMBOLS

3. GENERAL CHARACTERISTICS OF DIGITAL CHANNELS AND TRACTS

5. STANDARDS FOR PHASE JITTER AND PHASE DRIFT

PARAMETERS USED FOR ASSESSMENT

COMPLIANCE WITH OPERATIONAL REGULATIONS

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1. Electrical standards for main and zone cable lines

1.1 Electrical standards on the PRC line

At present, many transmission systems with frequency division of channels such as K-60 and KAMA are still in operation on the lines of the main and zonal networks of the Russian Armed Forces.

For the nominal lengths of amplifying sections with permissible deviations from them adopted for various transmission systems, standards have been established for the electrical parameters of symmetrical HF DC cables.

Table 1. Standards for electrical parameters of symmetrical RF cables running on direct current

1.2 Electrical standards on the DSP line

In modern digital transmission systems (DTS), used on trunk and zonal communication lines, the main type of analog-to-digital conversion is the receipt of a PCM signal from a message transmitted over a standard PM channel with an effective frequency band from 0.3 to 3.4 kHz.

The peculiarity of the PCM signal predetermines the structure of multi-channel DSPs as systems with time division of channels. In this case, systems of other channels are transmitted in a free time period.

Currently, DSPs form a set of systems (hierarchy) with mutually agreed upon transmission speeds: Primary, Secondary, Tertiary and Quaternary transmission systems.

The main technical characteristics of the DSP are given in Table 4.

Table 4. Technical characteristics of the DSP

1.3 New standard for electrical characteristics - trunk and zone cable lines

Application area:

The standard adopts the following definitions:

Transmission line is a set of physical circuits and (or) linear paths of transmission systems that have common linear structures, devices for their maintenance, as well as a propagation medium (GOST 22348).

Elementary cable section (ECU) - a section of a cable line together with mounted cable terminal devices.

A cable section (CS) is a set of electrical circuits connected in series at several adjacent ECUs for several transmission systems with equal distances between regenerators (amplifiers), but with a distance greater than the length of the ECU of a given line.

Regeneration section - a combination of an ECU or CS circuit with an adjacent regenerator.

OST 45.01-98 applies to ECU and KS, consisting of: - coaxial cables with pairs having washer, balloon or porous polyethylene insulation (cable types KM-4, KMA-4, KME-4, KM-8/6, MKT -4, MKTA-4 and VKPAP);

from symmetrical HF cables with cord-polystyrene or polyethylene insulation (cables of types MKS, MKSA, MKST, ZKP).

Coaxial and symmetrical HF cable transmission lines can be used for analog and digital systems for various ranges of transmitted frequencies and various transmission speeds (Tables 6, 7)

Table 6. Transmission systems via coaxial communication cables

2. Electrical standards for local communication lines

2.1 General provisions

The electrical characteristics of the installed local communication cable lines must meet the requirements given in industry standards:

OST 45.82-96. City telephone network. Subscriber cable lines with metal conductors. Operational standards. OST 45.83-96. Rural telephone network. Subscriber cable lines with metal conductors. Operational standards. OSTs came into force on January 1, 1998.

The standards apply to subscriber cable lines with metal cores of city telephone networks (AL GTS): electronic digital telephone exchanges; quasi-electronic telephone exchanges; coordinated automatic telephone exchanges; decade-step automatic telephone exchanges.

The standard establishes standards for the electrical parameters of AL GTS, STS circuits and their elements that ensure the functioning of:

1) telephone communication systems;

2) telegraph communication systems, including public telegraph services, subscriber telegraph, telex;

3) telematic services, including fax services, video text, e-mail, message processing;

4) data transmission systems;

5) systems for distribution of sound broadcasting programs;

6) digital systems with service integration.

The requirements of the standards must be taken into account during the operation, design, construction of new and reconstruction of existing lines of city telephone networks, as well as during certification tests.

2.2 Electrical standards for GTS cable lines

The structure of AL GTS electronic (EATS-90, MT-20), coordinate (ATSK, ATSKU) and ten-step (ATS-49, ATS-54) stations includes: main section; distribution area; subscriber wiring.

On AL GTS, cables of the TPP type with copper conductors with a diameter of 0.32 are used; 0.4 and 0.5; 0.64; 0.7 mm with polyethylene insulation and in a polyethylene sheath and TG type cables with copper conductors with a diameter of 0.4 and 0.5 mm with paper insulation and in a lead sheath.

For subscriber wiring, wires are used - single-pair telephone distribution wires with copper conductors with a diameter of 0.4 and 0.5 mm with polyethylene and polyvinyl chloride insulation, respectively.

Connections in cross-connections and distribution cabinets are made using cross-connecting wires of the PKSV brand with a copper core diameter of 0.4 and 0.5 mm.

Digital subscriber lines include:

lines connecting electronic telephone exchanges with group subscriber installations (digital concentrators, multiplexers);

lines connecting electronic telephone exchanges with digital subscriber installations;

lines connecting group subscriber installations with terminal digital subscriber installations;

lines made of cable type TPP with a core diameter of 0.4; 0.5 and 0.64 mm with a two-cable communication scheme;

lines of cables for digital transmission systems of the TPPZTs type with core diameters of 0.4 and 0.5 mm and TPPep-2E type with a core diameter of 0.64 mm with a single-cable communication arrangement.

At the ALC, cables of the TPP type are used for the section from the group subscriber installation to the distribution center. For subscriber wiring, specialized cables are used.

Electrical standards for subscriber lines of city telephone networks

The electrical resistance of 1 km of subscriber cable line circuits to direct current at an ambient temperature of 20 °C, depending on the cable used, is given in Table 8.

The value of the asymmetry of the resistance of the AL GTS cores to direct current should be no more than 0.5% of the circuit resistance.

Table 8. Electrical resistance of subscriber cable networks

4. Standards for electrical parameters of PV networks

4.1 Parameters of low-frequency networks of single-program wire broadcasting

The quality indicators of radio broadcasting paths are established by the state standard. For rural PV networks, quality class II is provided. The qualitative indicators of the PV tract are given in Table 16.

LIST OF ABBREVIATIONS, CONVENTIONS,
CHARACTERS

3. GENERAL CHARACTERISTICS OF DIGITAL
CHANNELS AND TRACTS

4. STANDARDS FOR ERROR RATES
DIGITAL CHANNELS AND NETWORK TRACTS

5. STANDARDS FOR PHASE JITTER INDICATORS
AND PHASE DRIFT