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FASCICLE III.4 Recommendations G.700 to G.795 GENERAL ASPECTS OF DIGITAL TRANSMISSION SYSTEMS; TERMINAL EQUIPMENTS |
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MONTAGE: PAGE 2 = PAGE BLANCHE 2 ^
SECTION 7
GENERAL ASPECTS OF DIGITAL TRANSMISSION SYSTEMS;
TERMINAL EQUIPMENTS
7.0 General
FRAMEWORK OF THE SERIES G.700, G.800 AND G.900 RECOMMENDATIONS
(former Recommendation G.701 of Volume III of the Yellow Book)
SECTION 7 -- General aspects of digital transmission systems; terminal equipments
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7.0 G.700 G.701 G.702 G.703 G.704 G.705 G.706 |
General Framework of the series G.700, G.800 and G.900 Recommendations Vocabulary of digital transmission and multiplexing, and pulse code modulation (PCM) terms Digital hierarchy bit rates Physical/electrical characteristics of hierarchical digital interfaces Functional characteristics of interfaces associated with network nodes Characteristics required to terminate digital links on a digital exchange Frame alignement and cyclic redundancy check (CRC) procedures relating to basic frame structures |
defined in Recommendation G.704
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G.707 G.708 G.709 7.1 G.711 G.712 |
Synchronous digital hierarcy bit rates Network node interface for the synchronous digital hierarchy Synchronous multiplexing structure Coding of analogue signals by pulse code modulation Pulse code modulation (PCM) of voice frequencies Performance characteristics of PCM channels between 4-wire interfaces at voice frequencies Fascicle III.4 -- Rec. G.700 3 |
G.713 Performance characteristics of PCM channels between 2-wire interfaces at voice frequencies 4 Fascicle III.4 -- Rec. G.700
G.714 Separate performance characteristics for the encoding and decoding sides of PCM channels applicable to 4-wire voice-frequency interfaces
G.715 Separate performance characteristics for the encoding and decoding side of PCM channels applicable to 2-wire interfaces
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7.2 G.721 G.722 G.723 G.724 G.725 7.3 G.731 G.732 G.733 G.734 G.735 |
Coding of analogue signals by methods other than PCM 32 kbit/s adaptive differential pulse code modulation (ADPCM) 7 kHz audio-coding within 64 kbit/s Extensions of Recommendation G.721 ADPCM to 24 and 40 kbit/s for DCME application Characteristics of a 48-channel low bit rate encoding primary multiplex operating at 1544 kbit/s System aspects for the use of the 7 kHz audio codec within 64 kbit/s Principal characteristics of primary multiplex equipment Primary PCM multiplex equipment for voice frequencies Characteristics of primary PCM multiplex equipment operating at 2048 kbit/s Characteristics of primary PCM multiplex equipment operating at 1544 kbit/s Characteristics of synchronous digital multiplex equipment operating at 1544 kbit/s Characteristics of primary PCM multiplex equipment operating at 2048 kbit/s and offering synchronous |
digital access at 384 kbit/s and/or 64 kbit/s
G.736 Characteristics of a synchronous digital multiplex equipment operating at 2048 kbit/s
G.737 Characteristics of an external access equipment operating at 2048 kbit/s offering synchronous digital access at 384 kbit/s and/or 64 kbit/s
G.738 Characteristics of primary PCM multiplex equipment operating at 2048 kbit/s and offering synchronous digital access at 320 kbit/s and/or 64 kbit/s
G.739 Characteristics of an external access equipment operating at 2048 kbit/s offering synchronous digital access at 320 kbit/s and/or 64 kbit/s
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7.4 Principal characteristics of second order multiplex equipments G.741 General considerations on second order multiplex equipments G.742 Second order digital multiplex equipment operating at 8448 kbit/s |
and using positive justification |
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G.743 Second order digital multiplex equipment operating at 6312 kbit/s |
and using positive justification |
Fascicle III.4 -- Rec. G.700 5
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G.744 G.745 G.746 |
Second order PCM multiplex equipment operating at 8448 kbit/s Second order digital multiplex equipment operating at 8448 kbit/s and using positive/zero/negative Characteristics of second order PCM multiplex equipment operating at 6312 kbit/s |
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G.747 |
Second order digital multiplex equipment operating at 6312 kbit/s and multiplexing three tributaries at 2048 |
6 Fascicle III.4 -- Rec. G.700
7.5 Principal characteristics of higher order multiplex equipments
G.751 Digital multiplex equipments operating at the third order bit rate of 34 | 68 kbit/s and the fourth order bit rate of 139 | 64 kbit/s and using positive justification
G.752 Characteristics of digital multiplex equipments based on a second order bit rate of 6312 kbit/s and using positive justification
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G.753 |
Third order digital multiplex equipment operating at 34 | 68 kbit/s and using positive/zero/negative Fourth order digital multiplex equipment operating at 139 | 64 kbit/s and using positive/zero/negative |
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justification G.755 |
Digital multiplex equipment operating at 139 | 64 kbit/s and multiplexing three tributaries at 44736 kbit/s |
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7.6 G.761 G.762 G.763 |
Principal characteristics of transcoder and digital circuit multiplication equipments General characteristics of a 60-channel transcoder equipment General characteristics of a 48-channel transcoder equipment Digital circuit multiplication equipment using 32 kbit/s ADPCM and digital speech interpolation |
7.7 Operations administration and maintenance features of transmission equipments
G.771 Q-interfaces and associated protocols for transmission equipment in the telecommunications management network (TMN)
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G.772 7.9 G.791 G.792 G.793 G.794 G.795 |
Digital protocol monitoring points Other terminal equipments General considerations on transmultiplexing equipments Characteristics common to all transmultiplexing equipments Characteristics of 60-channel transmultiplexing equipments Characteristics of 24-channel transmultiplexing equipments Characteristics of codecs for FDM assemblies |
SECTION 8 -- Digital networks
Fascicle III.4 -- Rec. G.700 7
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8.0 G.801 G.802 8.1 G.810 G.811 |
General aspects of digital networks Digital transmission models Interconnection between networks based on different digital hierarchies and speech encoding laws Design objectives for digital networks Considerations on timing and synchronization issues Timing requirements at the outputs of primary reference clocks suitable for plesiochronous operation of |
international digital links
G.812 Timing requirements at the outputs of slave clocks suitable for plesiochronous operation of international digital links
8 Fascicle III.4 -- Rec. G.700
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8.2 G.821 G.822 |
Quality and availability targets Error performance of an international digital connection forming part of an integrated services digital Controlled slip rate objectives on an international digital connection |
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G.823 G.824 |
The control of jitter and wander within digital networks which are based on the 2048 kbit/s hierarchy The control of jitter and wander within digital networks which are based on the 1544 kbit/s hierarchy |
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SECTION 9 -- Digital sections and digital line systems 9.0 General G.901 General considerations on digital sections and digital line systems 9.1 Digital line sections at hierarchical bit rates based on a rate of 1544 |
kbit/s |
Recommendations G.911 to G.915 have been deleted
9.2 Digital sections at hierarchical bit rates based on a primary bit rate of 2048 kbit/s
G.921 Digital sections based on the 2048 kbit/s hierarchy
9.3 Digital line transmission systems on cable at non-hierarchical bit rates
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G.931 9.4 G.941 9.5 |
Digital line sections at 3152 kbit/s Digital line systems provided by FDM transmission bearers Digital line systems provided by FDM transmission bearers Digital line systems Fascicle |
III.4 -- Rec. G.700 9 |
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G.950 G.951 G.952 G.953 G.954 G.955 G.956 |
General considerations on digital line systems Digital line systems based on the 1544 kbit/s hierarchy on symmetric pair cables Digital line systems based on the 2048 kbit/s hierarchy on symmetric pair cables Digital line systems based on the 1544 kbit/s hierarchy on coaxial pair cables Digital line systems based on the 2048 kbit/s hierarchy on coaxial pair cables Digital line systems based on the 1544 kbit/s hierarchy on optical fibre cables Digital line systems based on the 2048 kbit/s hierarchy on optical fibre cables |
9.6 Digital section and digital transmission systems for ISDN customer access
G.960 Digital section for ISDN basic rate access
G.961 Digital transmission system on metallic local lines for ISDN basic rate access
10 Fascicle III.4 -- Rec. G.700
(H.T.=OUI) TAB.??? FICHIER: H.T. = (34.TA.341.E) (SANS FORMULES)
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Tableaux: 2 -- Tabulateurs: 1 d) Formules: 0 -- Tabulateurs: 0 TEXTE (tabulateurs) |
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E: D. 2 NF01/006 = OPM: 02 Primary group A D. 2 NF01/039 = OPM: 02 -- D. 2 NF01/039 = OPM: 02 hetero D. 3 NF01/004 = OPM: 03 |
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(cs,1) (BT10) (BT20) |
Disk 2 NF01/054 (OPM = 02) Disk 2 NF01/028 (OPM = 02) Disk 2 NF01/051 (OPM = 02) |
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(A1.23e) / [26e] FOLIOS: 7 -- 44 (DO PRC.COSY.2) MEP [PA1] : OK= [1] Saisie diskette 17.11.89 YB ID + Verif.´ + diskette MAJ + laser 19.12.89 KJ Corr. LASER (1re epreuve)´ = 3eme Espaces reserv´ es´ + Transfert + Impr. |
MEP + LASER 20.02.90 GH/PC
Corr. MEP
Insertion des tableaux (tabulateurs .)
Fascicle III.4 -- Rec. G.701 11
BAT 5.04.90 PM
MAJ s/disquettes
12 Fascicle III.4 -- Rec. G.701
VOCABULARY OF DIGITAL TRANSMISSION AND MULTIPLEXING,
AND PULSE CODE MODULATION (PCM) TERMS
This Recommendation provides a vocabulary of terms and definitions that are appropriate to digital and pulse code modulation multiplexing and transmission systems.
A small number of the terms in the Recommendation are duplicated in Recommendation I.112. References to these definitions are given in parenthesis as an aid to ensuring consistency between the two Recommendations in the event of future amendments.
According to the conventions applied in this Recommendation any term in common usage, but whose use is deprecated in the sense defined, is shown after the recommended term as in the following example: ``2026 controlled slip [slip]''.
Where a truncated term is widely used in an understood context the complete term is quoted following the colloquial form, for example: ``1007 circuit, telecommunication circuit''.
Furthermore, any term which is in general use in addition to the principal term is shown after the principal term as in the following example: ``6002 timing recovery (timing extraction)''.
In the interest of standardization in the drafting of documents the following abbreviations are recommended:
kbit/s,
Mbit/s,
Gbit/s.
To avoid misinterpretation of the use of the point (.) and the comma (,) in different languages to separate the whole and decimal parts, it is recommended that the use of decimals should be avoided wherever possible. For example, ``2048 kbit/s'' is preferred to ``2.048 Mbit/s'' or ``2,048 Mbit/s.
Annex A to this Recommendation contains an alphabetical list of all of the terms defined in this Recommendation.
CONTENTS
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2.1 2.2 2.3 2.4 |
General Digital signals Digital transmission Digital multiplexing |
Fascicle III.4 -- Rec. G.701 13 |
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2.5 2.6 2.7 2.8 2.9 |
Frame alignment Timing Synchronization Pulse code modulation Codes |
Annex A -- Alphabetical List
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2.1 1001 |
General signal [102] |
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F: S: |
signal sen~ al |
A physical phenomenon one or more of whose characteristics may vary to represent information. 14 Fascicle III.4 -- Rec. G.701
1002 analogue signal [103]
F: signal analogique
S: sen~ al analogica´
A signal one of whose characteristic quantities follows continuously the variations of another physical quantity representing information.
1003 discretely-timed signal [104]
F: signal (temporel) discret
S: sen~ al discretamente temporizada
A signal composed of successive elements in time, each element having one or more characteristics which can convey information, for example, its duration, its waveform and its amplitude.
1004 transmission [106]
F: transmission
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S: transmision´ The action of conveying signals from one point to one or more other points. Note 1 -- Transmission can be effected directly or indirectly, with or without intermediate storage. Note 2 -- The use of the English word ``transmission'' in the sense of ``emission'' is deprecated. |
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1005 |
channel, transmission channel [108] F: voie, voie de transmission S: canal, canal de transmision´ A means of unidirectional transmission of signals between two points. Note 1 -- Several channels may share a common path; for example each channel may be allocated a particular |
frequency band or a particular time slot.
Note 2 -- The term may be qualified by the nature of the transmitted signals, by the bandwidth, by the digit rate, or by an arbitrary designation.
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Note 3 -- See also Recommendation I.112, Term 414, access channel. |
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1006 |
telecommunication [110] F: tel´ ecommunication´ S: telecomunicacion´ Any transmission and/or emission and reception of signals representing signs, writing, images and sounds or |
intelligence of any nature by wire, radio, optical or other electromagnetic systems.
1007 circuit, telecommunication circuit [111]
Fascicle III.4 -- Rec. G.701 15
F: circuit, circuit de tel´ ecommunications´
S: circuito, circuito de telecomunicacion´
A combination of two transmission channels permitting bidirectional transmission of signals between two points, to support a single communication.
Note 1 -- If the telecommunication is by nature unidirectional (for example: long distance television transmission), the term ``circuit'' is sometimes used to designate the single channel providing the facility.
Note 2 -- In a telecommunication network, the use of the term ``circuit'' is generally limited to a telecommunication circuit directly connecting two switching devices or exchanges, together with associated terminating equipment.
16 Fascicle III.4 -- Rec. G.701
Note 3 -- A telecommunication circuit may permit transmission in both directions simultaneously (duplex), or not simultaneously (simplex).
Note 4 -- A telecommunication circuit that is used for transmission in one direction only is sometimes referred to as a unidirectional telecommunication circuit. A telecommunication circuit that is used for transmission in both directions (whether simultaneously or not) is sometimes referred to as a bidirectional telecommunication circuit.
1008 interface [408]
F: jonction (interface)
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S: interfaz The common boundary between two associated systems. |
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2.2 2001 |
Digital signals digit F: el´ ement´ numerique´ S: digito´ A member selected from a finite set. Note 1 -- In digital transmission, a digit may be represented by a signal element, being characterized by the |
dynamic nature, discrete condition and discrete timing of the element, for example it may be represented as a pulse of specified amplitude and duration.
Note 2 -- In equipment used in digital transmission, a digit may be represented by a stored condition being characterized by a specified physical condition, for example it may be represented as a binary magnetic condition of a ferrite core.
Note 3 -- The context of the use of the term should be such as to indicate the radix of notation. (The meaning of ``digit'' in Notes 1, 2 and 3 translates into French as ``el´ ement´ numerique''.)´
Note 4 -- In telephone subscriber numbering, a digit is any of the numbers 1, 2, 3 . | | 9 or 0 forming the elements of a telephone number (Recommendation Q.10 [1]). (This meaning of ``digit'' translates into French as ``chiffre''.)
2002 binary figure
F: chiffre binaire
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S: cifra binaria One of the two figures (that is, 0 or 1) used in the representation of numbers in binary notation. |
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2003 |
binary digit (bit) F: el´ ement´ binaire S: digito´ binario (bit) A member selected from a binary set. Fascicle III.4 -- Rec. G.701 |
17 |
Note 1 -- Bit is an abbreviation for binary digit.
Note 2 -- In the interest of clarity, it is recommended that the term ``bit'' should not be used in two-condition start-stop modulation instead of ``unit element''.
2004 octet
F: octet
S: octeto
A group of eight binary digits or eight signal elements representing binary digits operated upon as an entity.
18 Fascicle III.4 -- Rec. G.701
2005 code word [character signal]
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S: palabra de codigo´ [sen~ al de caracter]´ |
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A set of signal elements representing the quantized value of a sample in PCM. Note -- In PCM, the term ``PCM word'' may be used in this sense. |
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2006 |
digital signal [105] F: signal numerique´ S: sen~ al digital |
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A discretely timed signal in which information is represented by a number of well-defined discrete values that one |
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of its |
characteristic quantities may take in time. Note -- The term may be qualified to indicate the digit rate, for example: ``140 Mbit/s digital signal''. |
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2007 |
signal element F: el´ ement´ de signal S: elemento de sen~ al |
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A part of a digital signal, characterized by its discrete timing and its discrete value, and used to represent a digit. |
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2008 |
digit position F: position d'un el´ ement´ de signal; position d'un el´ ement´ numerique´ S: posicion´ de digito´ The position in time or space into which a representation of a digit may be placed. |
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2009 |
n-ary digital signal F: signal numerique´ n-aire S: sen~ al digital n-aria |
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A digital signal in which each signal element has one of n permitted discrete values. |
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2010 |
redundant digital signal F: signal numerique´ redondant S: sen~ al digital redundante |
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The signal that is produced by encoding a given signal in accordance with a redundant line code. |
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2011 |
redundant n-ary signal Fascicle III.4 -- Rec. G.701 19 |
F: signal n-aire redondant
S: sen~ al n-aria redundante
A digital signal whose elements can assume n | iscrete states where the average equivalent binary content per signal element is less than log2n .
Note -- The relative redundancy R , of an n -ary digital signal, is given by:
R = 1 --
@ { fIr~e } over { fIr~d~~×~log~2n } @ =
@ left [ 1~-- { fIr~e } over { fIr~d~~×~log~2n } right ] @
× 100%
where rdis the symbol rate of the n -ary signal and reis the equivalent bit rate.
This may also be expressed in terms of the number of binary digits which can be transmitted by an element of a particular line code. Examples are:
AMI (37% redundant), 1 binary digit per element;
4B3T (16% redundant), 1.33 binary digit per element.
20 Fascicle III.4 -- Rec. G.701
2012 pseudo n-ary signal
F: signal pseudo n-aire
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S: sen~ al seudo n-aria |
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A redundant n -ary digital signal that is derived from a m -ary digital signal without change of the line digit rate. Note -- An alternate mark inversion signal is an example of a pseudo-ternary signal, i.e. n = 3, m = 2. |
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2013 |
digit rate F : debit´ numerique´ S: velocidad digital The number of digits per unit time. Note 1 -- An appropriate adjective may precede the word ``digit'', for example, binary digit rate. Note 2 -- In the interests of clarity it is recommended that this term should not be used to express the symbol rate |
on the line.
2014 line digit rate [symbol rate]
F: debit´ numerique´ en ligne [debit´ de symboles]
S: velocidad digital de linea [velocidad de simbolos]´
The number of signal elements of the line signal transmitted per unit time.
Note 1 -- The baud is usually used to quantify this, one baud being equal to one single element per second.
Note 2 -- Modulation rate is the term used in telegraphy and data communication; it is the reciprocal of the duration of the unit interval.
2015 equivalent binary content
F: contenu binaire equivalent´
S: contenido binario equivalente
The number of binary digits strictly necessary to convey the same information as a defined number of signal elements in a given digital signal.
2016 equivalent bit rate
F: debit´ binaire equivalent´
S: velocidad binaria equivalente
The value of the bit rate strictly necessary to convey the same information in the same time as a given digital signal at a given digit rate.
2017 significant instant, significant instant of a digital signal
Fascicle III.4 -- Rec. G.701 21
F: instant significatif, instant significatif d'un signal numerique´
S: instante significativo, instante significativo de una sen~ al digital
The instant at which a signal element commences in a discretely-timed signal. 22 Fascicle III.4 -- Rec. G.701
2018 unit interval
F: intervalle unitaire
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S: intervalo unitario (o intervalo unidad) The nominal difference in time between consecutive significant instants of an isochronous signal. |
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2019 |
decision instant, decision instant of a digital signal F: instant de decision,´ instant de decision´ d'un signal numerique´ S: instante de decision´ instante de decision´ de una sen~ al digital |
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The instant at which a decision is taken as to the probable value of signal element of a received digital signal. |
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2020 |
decision circuit F: circuit de decision´ S: circuito de decision´ A circuit that decides the probable value of a signal element of a received digital signal. |
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2021 |
regeneration F: reg´ en´ eration´ S: regeneracion´ The process of receiving and reconstructing a digital signal so that the amplitudes, waveforms and timing of its |
signal elements are constrained within specified limits.
2022 regenerator
F: reg´ en´ erateur´
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S: regenerador A device that performs regeneration. |
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2023 |
regenerative repeater F: rep´ eteur´ reg´ en´ erateur´ S: repetidor regenerativo A repeater that regenerates digital signals. Note 1 -- A regenerative repeater may operate in one or both directions of transmission, and the term may be |
qualified by ``unidirectional'' or ``bidirectional'' as appropriate.
Note 2 -- Repeater is defined in Recommendation G.601.
Fascicle III.4 -- Rec. G.701 23
2024 jitter
F: gigue
S: fluctuacion´ de fase
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Short-term non-cumulative variations of the significant instants of a digital signal from their ideal positions in time. |
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2025 |
wander F: derapage´ S: fluctuacion´ lenta de fase Long term non-cumulative variations of the significant instants of a digital signal from their ideal positions in time. |
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24 |
Fascicle III.4 -- Rec. G.701 |
2026 controlled slip [slip]
F: glissement commande´ [saut]
S: deslizamiento controlado [deslizamiento]
The irretrievable loss or gain of a set of consecutive digit positions in a digital signal, in which both the magnitude and instant of that loss or gain are controlled, to enable the signal to accord with a rate different from its own.
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Note -- Where appropriate the term may be qualified, for example: controlled octet slip, controlled frame slip. |
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2027 |
uncontrolled slip F: glissement non commande´ S: deslizamiento incontrolado The loss or gain of a digit position or a set of consecutive digit positions in a digital signal resulting from an |
aberration of the timing processes associated with transmission or switching of a digital signal, and in which either the magnitude or the instant of that loss or gain is not controlled.
2028 scrambler
F: embrouilleur
S: aleatorizador
A device that converts a digital signal into a pseudo-random digital signal having the same meaning and the same digit rate.
2029 descrambler
F: desembrouilleur´
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S: desaleatorizador A device that performs the complementary operation to that of a scrambler. |
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2030 |
error, digital error F: erreur, erreur numerique´ S: error, error digital An inconsistency between a digit in a transmitted digital signal and the corresponding digit in the received digital |
signal.
2031 error ratio [error rate]
F: taux d'erreur [rapport d'erreur]
S: tasa de errores [proporcion´ de errores]
The ratio of the number of digital errors received in a specified period to the total number of digits received in the same period.
Fascicle III.4 -- Rec. G.701 25
Note 1 -- Numerical values of error ratio should be expressed in the form
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n | (mu | 0D where p is a positive integer. |
DlF261 |
lF261 |
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Note 2 -- Error ratio may be qualified, for example by the term ``bit'' or ``block''. |
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2032 |
error multiplication F: multiplication d'erreurs S: multiplicacion´ de errores The property of an apparatus whereby a single digital error in the input signal presented to it results in more than |
one digital error in the output signal.
Note -- Line code converters and descramblers are examples of apparatus that may cause error multiplication.
26 Fascicle III.4 -- Rec. G.701
2033 error multiplication factor
F: facteur de multiplication d'erreurs
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S: factor de multiplicacion´ de errores The ratio of the number of digital errors in the output signal to the number of digital errors in the input signal. Note -- The error multiplication factor may be expressed as either an average or maximum value. |
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2034 |
error spread F: etalement´ d'erreurs [repartition´ des erreurs] S: dispersion´ de errores The number of consecutive digits of the output signal over which digital errors are distributed when a single digital |
error in the input signal causes error multiplication.
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2.3 3001 |
Digital transmission digital transmission [107] |
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F: S: |
transmission numerique´ transmision´ digital |
The transmission of digital signals by means of a channel or channels that may assume in time any one of a defined set of discrete states.
3002 digital channel, digital transmission channel [109]
F: voie numerique,´ voie de transmission numerique´
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S: canal digital, canal de transmision´ digital The means of unidirectional digital transmission of digital signals between two points. |
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3003 |
digital circuit, digital telecommunication circuit [112] F: circuit numerique,´ circuit numerique´ de tel´ ecommunications´ S: circuito´ digital, circuito de telecomunicacion´ digital A combination of two digital transmission channels permitting bidirectional digital transmission in both directions |
between two points, to support a single communication.
Note 1 -- If the telecommunication is by nature unidirectional (for example, long-distance television transmission), the term ``digital circuit'' is sometimes used to designate the single digital channel providing the facility.
Note 2 -- In a telecommunication network, use of the term ``digital circuit'' is generally limited to a digital telecommunication circuit directly connecting two switching devices or exchanges, together with associated terminating equipment.
Fascicle III.4 -- Rec. G.701 27
Note 3 -- A digital telecommunication circuit may permit transmission in both directions simultaneously (duplex), or not simultaneously (simplex).
Note 4 -- A digital telecommunication circuit that is used for transmission in one direction only is sometimes referred to as a unidirectional digital telecommunication circuit. A digital telecommunication circuit that is used for transmission in both directions (whether simultaneously or not) is sometimes referred to as a bidirectional digital telecommunication circuit.
3004 digital connection [310]
F: connexion numerique´
S: conexion´ digital
A concatenation of digital transmission channels or digital telecommunication circuits, switching and other functional units set up to provide for the transfer of digital signals between two or more points in a telecommunication network, to support a single communication.
28 Fascicle III.4 -- Rec. G.701
3005 digital link, digital transmission link [digital path] [302]
F: liaison numerique,´ liaison de transmission numerique´ [conduit numerique]´
S: enlace digital, enlace de transmision´ digital [trayecto digital]
The whole of the means of digital transmission of a digital signal of specified rate between two digital distribution frames (or equivalent).
Note 1 -- A digital link comprises one or more digital sections and may include multiplexing and/or demultiplexing, but not switching.
Note 2 -- The term may be qualified to indicate the transmission medium used, for example, ``digital satellite link''.
Note 3 -- The term always applies to the combination of ``go'' and ``return'' directions of transmission, unless stated otherwise.
Note 4 -- The term ``digital path'' is sometimes used to describe one or more digital links connected in tandem, especially between equipments at which the signals of the specified rate originate and terminate.
3006 digital distribution frame
F: repartiteur´ numerique´
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S: repartidor digital A structure that provides flexibility of semipermanent interconnection of digital channels or digital circuits. Note -- Digital sections and digital links normally terminate at digital distribution frames. Figure 1/G.701 gives examples of digital sections, digital links, digital line sections, etc. 3007 digital section |
F: section numerique´
S: seccion´ digital
The whole of the means of digital transmission of a digital signal of specified rate between two consecutive digital distribution frames or equivalent.
Note 1 -- A digital section forms either a part or the whole of a digital link, and includes terminating equipments at both ends, but excludes multiplexers.
Note 2 -- Where appropriate, the digital rate or multiplex order should qualify the title.
Note 3 -- The definition applies to the combination of ``go'' and ``return'' directions of transmission, unless stated otherwise.
3008 section termination
F: extremit´ e´ de section
S: extremo de seccion´
A connectional interface selected to be the boundary between a physical transmission medium and its associated equipment.
Note -- This point will usually be the connectors at the input and output of an equipment.
Fascicle III.4 -- Rec. G.701 29
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3009 |
elementary cable section [repeater section] F: section el´ ementaire´ de c| ble [section (el´ ementaire)´ d'amplification] S: seccion´ elemental de cable [seccion´ con amplificacion]´ The whole of the physical transmission medium between the section termination at the output of one equipment |
and the section termination at the input of the following equipment.
Note 1 -- An elementary cable section usually consists of several factory lengths of cable connected together and any associated accessories (such as flexible cables) necessary to connect it to the section terminals.
Note 2 -- Examples of the physical transmission media are a coaxial or symmetric pair, and optical fibre.
30 Fascicle III.4 -- Rec. G.701
3010 elementary repeater section
F: section el´ ementaire´ amplifiee´
S: seccion´ elemental de repeticion´
In a given direction of transmission, an elementary cable section together with the immediately following analogue repeater.
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3011 |
elementary regenerator section [regenerator section] F: section el´ ementaire´ reg´ en´ er´ ee´ [section de reg´ en´ eration]´ S: seccion´ elemental de regeneracion´ [seccion´ de regeneracion]´ In a given direction of transmission, an elementary cable section together with the immediately following |
regenerative repeater.
3012 digital line section
F: section de ligne numerique´
S: seccion´ de linea´ digital
A digital section implemented on a single type of manufactured transmission medium, such as symmetric pair, coaxial pair, or optical fibre.
Note -- A digital line section includes line terminating equipments at both ends, and regenerative repeaters if needed, but excludes multiplexers.
3013 digital line link [digital line path]
F: liaison de ligne numerique´ [conduit de ligne numerique]´
S: enlace de linea´ digital [trayecto de linea´ digital]
A digital link that comprises a digital line section or a number of tandem-connected digital line sections.
3014 digital transmission system
S: sistema de transmision´ digital
A specific means of providing a digital section.
3015 digital line system
S: sistema de linea´ digital
A digital transmission system that provides a digital line section.
Fascicle III.4 -- Rec. G.701 31
3016 digital radio section
F: section radioelectrique´ numerique´
|
S: seccion´ radiodigital A digital section implemented on a radio-relay system. |
||
|
3017 |
digital radio link [digital radio path] F: liaison radioelectrique´ numerique´ [conduit radioelectrique´ numerique]´ S: enlace radiodigital, [trayecto radiodigital] A digital link that comprises a digital radio section or a number of tandem-connected digital radio sections. |
|
|
32 |
Fascicle III.4 -- Rec. G.701 |
3018 digital radio system
|
S: sistema radiodigital A digital transmission system that provides a digital radio section. |
||
|
3019 |
bit sequence independence F: independance´ de la sequence´ des bits S: independencia de la secuencia de bits The property of a binary transmission channel, telecommunication circuit or connection, that permits all |
sequences of binary signal elements to be conveyed over it at its specified bit rate, without change to the value of any signal elements.
Note -- Practical transmission systems that are not completely bit sequence independent may be described as quasi bit sequence independent. In such cases the limitations should be clearly stated.
3020 digit sequence integrity
F: integrit´ e´ de la suite des el´ ements´ numeriques´
S: integridad de la secuencia de digitos´
The property of a digital transmission channel, telecommunication circuit or connection, that permits a digital signal to be conveyed over it without change to the order of any signal elements.
3021 octet sequence integrity
F: integrit´ e´ de la suite des octets
S: integridad de la secuencia de octetos
The property of a digital transmission channel, telecommunication circuit or connection that permits a digital signal to be conveyed over it without change to the order of any octets.
3022 transparency, digital transparency
F: transparence, transparence numerique´
S: transparencia, transparencia digital
The property of a digital transmission channel, telecommunication circuit or connection, that permits any digital signal to be conveyed over it without change to the value or order of any signal elements.
Note -- The digital transmission channel, telecommunication circuit or connection concerned may introduce delay, and may contain reversible code conversion functions.
3023 alarm indication signal (AIS)
F: signal d'indication d'alarme (SIA)
Fascicle III.4 -- Rec. G.701 33
|
3024 |
S: sen~ al de indicacion´ de alarma (SIA) A signal that replaces the normal traffic signal when a maintenance alarm indication has been activated. upstream failure indication F: indication de defaillance´ en amont S: indicacion´ de fallo atras´ An indication provided by a digital multiplexer, line section or a radio section, that a signal applied at its input port |
is outside its prescribed maintenance limit.
34 Fascicle III.4 -- Rec. G.701
3025 service digits [housekeeping digits]
F: el´ ements´ numeriques´ de service
S: digitos´ de servicio
Digits that are added, to a digital signal at the sending end of a digital link, normally at regular intervals and removed at the receiving end of that link and used to provide ancillary facilities.
Figure 1/G.701, p.
Fascicle III.4 -- Rec. G.701 35
|
2.4 4001 |
Digital multiplexing highway (American: bus) |
||||
|
F: S: |
bus (jonction multiplex interne) [canal] arteria (bus) |
A common path within an apparatus or station over which pass signals from a number of channels identified by time division.
4002 channel gate
F: porte de canal
|
S: puerta de canal A device for connecting a channel to a highway, or a highway to a channel, at specified times. |
||
|
4003 |
digital multiplex hierarchy F: hierarchie´ de multiplexage numerique´ S: jerarquia´ de los mulitplex´ digitales A series of digital multiplexers graded according to capability so that multiplexing at one level combines a defined |
number of digital signals, each having the digit rate prescribed for a lower order, into a digital signal having a prescribed digit rate which is then available for further combination with other digital signals of the same rate in a digital multiplexer of the next higher order.
4004 primary digital group
F: groupe numerique´ primaire
S: grupo digital primario
An assembly, by digital multiplexing, of digital signals occupying a specified number of channel time-slots to form a composite signal having a digit rate of 2048 kbit/s or 1544 kbit/s.
|
Note -- Normally each channel time-slot has eight digit time-slots and an effective digit rate of 64 kbit/s. |
||
|
4005 |
primary PCM group [primary block] (American: digroup) F: groupe primaire MIC [bloc primaire] S: grupo primario MIC [bloque primario] An assembly, by digital multiplexing, of PCM signals occupying a specified number of channel time-slots to form |
a composite signal having a digit rate of 1544 kbit/s or 2048 kbit/s, in both directions of transmission.
Note -- The following conventions could be useful:
Primary group m -- a basic group of PCM signals derived from 1544-kbit/s PCM multiplex equipment.
36 Fascicle III.4 -- Rec. G.701
|
4006 |
Primary group A -- n-ary digital group F: groupe numerique´ n-aire S: grupo digital n-ario |
a basic group of PCM signals derived from 2048-kbit/s PCM multiplex equipment. |
A number of primary digital or pcm groups assembled by digital multiplexing to form a composite signal of specified digit rate, in both directions of transmission.
Note 1 -- A secondary digital group may comprise four primary digital or pcm groups to form a composite signal having a digit rate of 8448 or 6312 kbit/s.
Fascicle III.4 -- Rec. G.701 37
Note 2 -- A tertiary digital group may comprise four 8448 kbit/s secondary digital groups or five or seven 6312 kbit/s secondary digital groups to form a composite signal having a digit rate of 34368, 32064 or 44736 kbit/s.
Note 3 -- A quaternary digital group may comprise four 34368 kbit/s tertiary digital groups to form a composite signal having a digit rate of 139264 kbit/s.
4007 frame
F: trame
|
S: trama A cyclic set of consecutive time slots in which the relative position of each time slot can be identified. |
||
|
4008 |
multiframe F: multitrame S: multitrama A cyclic set of consecutive frames in which the relative position of each frame can be identified. |
|
|
4009 |
subframe F: sous-trame, secteur de trame S: subtrama A sequence of noncontiguous time-slots within a frame, each occurring at n times the frame repetition rate |
where n is an integer >1.
4010 parallel to serial converter (American: serializer) [dynamicizer]
|
S: convertidor paralelo/serie A device that converts a group of signal elements, all of which are |
presented |
simultaneously, |
into |
a |
||||
|
corresponding sequence of consecutive signal elements. 4011 serial to parallel converter (American: deserializer) [staticizer] |
S: convertidor serie/paralelo
|
A device that converts a sequence of consecutive signal elements into a corresponding group of signal elements |
||
|
all of 4012 |
which are presented simultaneously. time-division multiplexing F: multiplexage temporel [multiplexage par repartition´ dans le temps] S: multiplexacion´ por division´ en el tiempo |
|
|
38 |
Fascicle III.4 -- Rec. G.701 |
|
4013 |
Multiplexing in which several signals are interleaved in time for transmission over a common channel. digital multiplexing F: multiplexage numerique´ S: multiplexacion´ digital A form of time division multiplexing applied to digital channels which convey digital signals. Fascicle III.4 -- Rec. G.701 39 |
4014 digital multiplexer
F: multiplexeur numerique´
S: multiplexor digital
|
Equipment that combines by time-division multiplexing several digital signals into a single composite digital signal. |
||
|
4015 |
digital demultiplexing F: demultiplexage´ numerique´ S: demultiplexacion´ digital The separation of a composite digital signal into its component digital signals. |
|
|
4016 |
digital demultiplexer F: demultiplexeur´ numerique´ S: demultiplexor digital Equipment that separates a composite digital signal into its component digital signals. |
|
|
4017 |
digital multiplex equipment F: equipement´ de multiplexage numerique´ S: equipo multiplex´ digital The combination of a digital multiplexer and a digital demultiplexer at the same location, operating in opposite |
directions of transmission.
4018 PCM multiplex equipment
F: equipement´ de multiplexage MIC
S: equipo multiplex´ MIC
Equipment that derives a single digital signal at a defined digit rate from several voice frequency channels by a combination of pulse code modulation and time division multiplexing, and that also carries out the complementary functions in the opposite direction of transmission.
4019 digital block
F: bloc numerique´
|
S: bloque digital The combination of a digital link and associated digital multiplex equipments. Note -- The bit rate of the digital link should form part of the title. |
|||
|
4020 40 |
transmultiplexer Fascicle III.4 -- Rec. G.701 |
F: transmultiplexeur
S: transmultiplexor
An equipment that transforms a frequency-division multiplexed signal (such as group or supergroup) into a corresponding time-division multiplexed signal that has the same structure as if it had been derived from PCM multiplex equipment, and that also carries out the complementary function in the opposite direction of transmission.
4021 digital filling [digital padding]
F: remplissage numerique´
S: relleno digital [complementacion´ digital]
The addition of signal elements at regular intervals to a digital signal to change the digit rate from its original value to a predetermined higher value.
Note -- The added digits are not normally used to transmit information.
Fascicle III.4 -- Rec. G.701 41
4022 justification [stuffing, pulse stuffing]
F: justification
S: justificacion´ [relleno de impulsos]
The process of changing the digit rate of a digital signal in a controlled manner so that it can accord with a digit rate different from its own inherent rate, usually without loss of information.
4023 positive justification [positive stuffing, positive pulse stuffing]
F: justification positive
S: justificacion´ positiva [relleno positivo de impulsos]
A method of justification in which the digit time-slots used to convey a digital signal have a digit rate that is always higher than the digit rate of that original signal.
Note 1 -- Positive justification is usually achieved by the provision of a fixed number of digit time-slots (justifiable digit time-slots) per frame in the resultant signal which may be used to transmit either information from the original signal, or no information, according to the relative digit rates of the resultant signal and the original signal.
Note 2 -- Information which indicates whether the justifiable digit time-slots contain information digits or justifying digits is conveyed by means of the justification service digits.
4024 negative justification [negative stuffing, negative pulse stuffing]
F: justification negative´
S: justificacion´ negativa [relleno negativo, relleno negativo de impulsos]
A method of justification in which the digit time-slots used to convey a digital signal have a digit rate that is always lower than the digit rate of that original signal.
Note 1 -- The deleted digits are conveyed by separate means.
Note 2 -- Information which facilitates the recovery of the deleted digits is conveyed by means of the justification service digits.
4025 positive/zero/negative justification [positive/zero/negative stuffing, positive/zero/negative pulse stuffing]
F: justification positive/nulle/negative´
S: justification´ positiva/nula/negativa [relleno positivo/nulo/negativo de impulsos]
A method of justification in which the digit time-slots used to convey a digital signal have a digit rate that may be higher than, the same as, or lower than the digit rate of the original signal.
Note 1 -- Justifiable digit time-slots are provided in accordance with Note 1 of 4023 above.
Note 2 -- Separate means of transmitting deleted digits are provided in accordance with Note 2 of 4024 above.
Note 3 -- Information which facilitates the recovery of the original digits, which are conveyed by means of the justification service digits.
Note 4 -- Usually the digit time-slots used to convey a digital signal have the same nominal digit rate as the original signal.
42 Fascicle III.4 -- Rec. G.701
4026 justifiable digit time-slot [stuffable digit time-slot]
F: creneau´ temporel el´ ementaire´ justifiable
S: intervalo de tiempo de digito´ justificable [intervalo de tiempo de digito´ rellenable]
A digit time-slot that is provided for the purpose of justification and which may contain either an information digit or a justifying digit.
Fascicle III.4 -- Rec. G.701 43
4027 justifying digit [stuffing digit]
F: el´ ement´ numerique´ de justification
|
S: digito´ de justificacion´ [digito´ de relleno] A digit inserted in a justifiable digit time-slot when that time slot is not required for an information digit. |
||
|
4028 |
justification service digit [stuffing service digit] F: el´ ement´ numerique´ de service de justification S: digito´ de servicio de justificacion´ [digito´ de servicio de relleno] A digit that transmits information concerning the status of a justifiable digit time-slot. |
|
|
4029 |
justification rate [stuffing rate] F: debit´ de justification S: velocidad de justificacion´ [velocidad de relleno] The rate at which justifying digits are inserted, or at which information digits are transmitted by other means. |
|
|
4030 |
nominal justification rate [nominal stuffing rate] F: debit´ nominal de justification S: velocidad nominal de justificacion´ [velocidad nominal de relleno] The justification rate that occurs when the digit rates of both the original signal and the justified signal are at their |
nominal values.
4031 maximum justification rate [maximum stuffing rate]
F: debit´ maximal de justification
S: velocidad maxima´ de justificacion´ [velocidad maxima´ de relleno]
The maximum possible justification rate that can be accommodated by a justification process.
Note -- In practice the tolerance limits of the original signal and of the system used to convey the justified signal might be such that the maximum justification rate is never realized.
4032 justification ratio [stuffing ratio]
F: taux de justification
S: relacion´ de justificacion´ [relacion´ de relleno]
The ratio of the actual justification rate to the maximum justification rate.
4033 nominal justification ratio [nominal stuffing ratio]
44 Fascicle III.4 -- Rec. G.701
F: taux nominal de justification
S: relacion´ nominal de justificacion´ [relacion´ nominal de relleno]
The ratio of the nominal justification rate to the maximum justification rate.
|
2.5 Frame alignment Similar definitions are applicable to multiframe alignment. 5001 |
frame alignment |
||
|
F: verrouillage de trame S: alineacion´ de trama |
The state in which the frame of the receiving equipment is synchronized with that of the received signal.
Fascicle III.4 -- Rec. G.701 45
5002 frame alignment signal
F: signal de verrouillage de trame
S: sen~ al de alineacion´ de trama
The distinctive signal inserted in every frame or once in every n frames, always occupying the same relative position within the frame, and used to establish and maintain frame alignment.
5003 bunched frame alignment signal
F: signal de verrouillage de trame concentre´
|
S: sen~ al de alineacion´ de trama concentrada |
||
|
A frame alignment signal whose signal elements occupy consecutive digit time slots. |
||
|
5004 |
distributed frame alignment signal F: signal de verrouillage de trame reparti´ [signal de verrouillage de trame distribue]´ S: sen~ al de alineacion´ de trama distribuida |
|
|
A frame alignment signal whose signal elements occupy non-consecutive digit time slots. |
||
|
5005 |
frame alignment recovery time F: temps de reprise du verrouillage de trame S: tiempo de recuperacion´ de la alineacion´ de trama The time that elapses between a valid frame alignment signal being available at the receive terminal equipment |
and frame alignment being established.
Note -- The frame alignment recovery time includes the time required for replicated verification of the validity of the frame alignment signal.
5006 out-of-frame alignment time
F: duree´ de perte du verrouillage de trame
|
S: duracion´ de la perdida´ de la alineacion´ de trama The time during which frame alignment is effectively lost. Note -- That time includes the time to detect loss of frame alignment and the frame alignment recovery time. |
|||
|
2.6 6001 46 |
Timing timing signal Fascicle III.4 -- Rec. G.701 |
F: signal de rythme
|
S: sen~ al de temporizacion´ |
|||
|
A cyclic signal used to control the timing of operations. |
|||
|
6002 |
timing recovery [timing extraction] F: recup´ eration´ du rythme S: recuperacion´ de la temporizacion´ [extraccion´ de la temporizacion] |
on]´ |
|
|
The derivation of a timing signal from a received signal. |
|||
|
Fascicle III.4 -- Rec. G.701 47 |
6003 retiming
F: reajustement´ du rythme
|
S: reajuste de la temporizacion´ Adjustment of the intervals between the significant instants of a digital signal, by reference to a timing signal. |
||
|
6004 |
time-slot F: creneau´ temporel [intervalle de temps] S: intervalo de tiempo [sector de tiempo, celda de tiempo] Any cyclic time interval that can be recognized and defined uniquely. |
|
|
6005 |
digit time-slot F: creneau´ temporel el´ ementaire´ [intervalle de temps el´ ementaire]´ S: intervalo de tiempo de digito´ A time slot allocated to a single digit. |
|
|
6006 |
channel time-slot F: creneau´ temporel de voie S: intervalo de tiempo de canal A time slot occupying a specific position in a frame and allocated to a particular time-derived channel. Note 1 -- Where appropriate a description may be added, for example ``telephone channel time slot''. Note 2 -- In addition to its main function of transmitting a character signal, a channel time slot may also be used |
for in-slot signalling or for transmitting other information.
6007 signalling time-slot
F: creneau´ temporel de signalisation
|
S: intervalo de tiempo de sen~ alizacion´ |
|||
|
A time slot occupying a specific position in a frame and allocated to the transmission of signalling. |
|||
|
6008 |
frame alignment time-slot F: creneau´ temporel de verrouillage de trame S: intervalo de tiempo de alineacion´ de trama A time slot occupying the same relative position in every frame and used to transmit the frame alignment signal. |
||
|
6009 48 |
clock Fascicle III.4 -- Rec. G.701 |
F: horloge
S: reloj
Equipment that provides a timing signal.
Note -- Where replicated sources are used for security reasons, the assembly of these is regarded as single clock.
Fascicle III.4 -- Rec. G.701 49
6010 reference clock
F: horloge de ref´ erence´
S: reloj de referencia
A clock of very high stability and accuracy that may be completely autonomous and whose frequency serves as a basis of comparison for the frequency of other clocks.
6011 master clock
F: horloge ma| tresse
|
S: reloj maestro A clock that is used to control the frequency of other clocks. |
||
|
6012 |
time interval error F: derive´ temporelle S: error de intervalo de tiempo The total difference over a specified interval of time in the significant instants of a digital signal from their ideal |
positions in time.
6013 relative time interval error
F: derive´ temporelle relative
S: error de intervalo de tiempo relativo
|
The total difference over a specified interval of time in the corresponding significant instants of two digital signals. |
||
|
6014 |
isochronous F: isochrone S: isocrono´ The essential characteristic of a time-scale or a signal such that the time intervals between consecutive |
significant instants either have the same duration or durations that are integral multiples of the shortest duration.
|
Note -- In practice, variations in the time intervals are constrained within specified limits. |
||
|
6015 |
anisochronous F: anisochrone S: anisocrono´ The essential characteristic of a time-scale or a signal such that the time intervals between consecutive |
significant instants do not necessarily have the same duration or durations that are integral multiples of the shortest duration.
50 Fascicle III.4 -- Rec. G.701
6016 synchronous [mesochronous]
F: synchrone [mesochrone]´
S: sincrono´ [mesocrono]´
The essential characteristic of time-scales or signals such that their corresponding significant instants occur at precisely the same average rate.
Note -- The timing relationship between corresponding significant instants usually varies between specified limits.
6017 homochronous
F: homochrone
S: homocrono´
The essential characteristic of time-scales or signals such that their corresponding significant instants have a constant, but uncontrolled, time relationship with each other.
Fascicle III.4 -- Rec. G.701 51
6018 non-synchronous [asynchronous/heterochronous]
F: nonsynchrone [asynchrone/het´ erochrone]´
S: no-sincrono´ [asicrono/heter´ ocrono]´
The essential characteristic of time-scales or signals such that their corresponding significant instants do not necessarily occur at the same average rate.
6019 plesiochronous
F: plesiochrone´
S: plesiochrono´
The essential characteristic of time-scales or signals such that their corresponding significant instants occur at nominally the same rate, any variation in rate being constrained within specified limits.
Note 1 -- Two signals having the same nominal digit rate, but not stemming from the same clock or homochronous clocks, are usually plesiochronous.
|
Note 2 -- There is no limit to the time relationship between corresponding significant instants. |
||
|
6020 |
heterochronous F: het´ erochrone´ S: heterocrono´ The essential characteristic of time-scales or signals such that their corresponding significant instants occur at |
different nominal rates.
Note 1 -- Two signals having different nominal digit rates, and not stemming from the same clock or from homochronous clocks are usually heterochronous.
|
Note 2 -- Terms 6015 to 6020 are based on the following Greek roots: iso = equal homo = same plesio = near hetero = different |
||
|
6021 |
codirectional interface F: interface codirectionnelle S: interfaz codireccional An interface across which the signals to be transferred and their associated timing signals are transmitted in the |
same direction.
6022 centralized-clock interface
52 Fascicle III.4 -- Rec. G.701
S: interfaz de reloj centralizado
An interface across which, for both directions of transmission of the signals to be transferred, the associated timing signals of both the exchange terminal on the line side and the exchange terminal on the service side are supplied from a centralized clock.
|
Note -- The timing of the centralized clock may be derived from a nominated incoming line signal. |
||
|
6023 |
contradirectional interface F: interface contradirectionnelle S: interfaz contradireccional An interface across which the timing signals associated with both directions of transmission of the signals to be |
transferred, are directed towards the same side of the interface.
Fascicle III.4 -- Rec. G.701 53
|
2.7 7001 |
Synchronization synchronization |
||||
|
F: S: |
synchronisation sincronizacion´ |
|
The process of adjusting the corresponding significant instants of signals to make them synchronous. |
||
|
7002 |
timing information F: information de rythme S: informacion´ de temporizacion´ Information contained in a signal relating to the timing of another signal. |
|
|
7003 |
synchronization information F: information de synchronisation S: informacion´ de sincronizacion´ Information that indicates the relationship between the timing of two or more signals. |
|
|
7004 |
clock control signal F: signal de commande d'horloge S: sen~ al de control de reloj |
|
|
A signal that directly controls the phase or frequency of a clock. |
||
|
7005 |
synchronization node F: noeud de synchronisation S: nodo de sincronizacion´ A point in a synchronized network at which synchronization information is derived, sent or received. |
|
|
7006 |
synchronization link F: liaison de synchronisation S: enlace de sincronizacion´ A link between two synchronization nodes over which synchronization information is transmitted. |
|
|
7007 54 |
synchronization network Fascicle III.4 -- Rec. G.701 |
F: reseau´ de synchronisation
S: red de sincronizacion´
An arrangement of synchronization nodes and synchronization links provided in order to synchronize the clocks at, or connected to, those nodes.
7008 single-ended synchronization
F: synchronisation locale [synchronisation unilaterale]´
S: sincronizacion´ uniterminal
A method of synchronizing a specified synchronization node with respect to another synchronization node in which synchronization information at the specified node is derived from the phase difference between the local clock and the incoming digital signal from the other node.
Fascicle III.4 -- Rec. G.701 55
|
7009 |
double-ended synchronization F: synchronisation locale et distante [synchronisation bilaterale]´ S: sincronizacion´ biterminal A method of synchronizing a specified synchronization node with respect to another synchronization node in |
which synchronization information at the specified node is derived by comparing the phase difference between the local clock and the incoming digital signal from the other node, with the phase difference at the other node between its local clock and the digital signal incoming from the specified node.
7010 unilateral control
F: synchronisation unilaterale´ [commande unilaterale]´
S: control unilateral
Control between two synchronization nodes such that the frequency of the clock of only one of these nodes is influenced by timing information derived from the clock of the other node.
7011 bilateral control
F: synchronisation bilaterale´ [commande bilaterale]´
S: control bilateral
Control between two synchronization nodes such that the frequency of the clock of each of these nodes is influenced by timing information derived from the clock of the other node.
7012 analogue control
F: synchronisation analogique [mode analogique]
S: control analogico´
A method of controlling clocks in which the clock control signal is a continuous (monotonic) function of the phase difference between clocks, at least over a limited range.
7013 linear analogue control
F: synchronisation analogique lineaire´ [mode analogique lineaire]´
S: control analogico´ lineal
Analogue control in which the clock control signal is proportional to the phase difference between clocks, at least over a limited range.
7014 amplitude quantized control
S: control por cuantificacion´ de amplitud
A method of controlling clocks in which the clock control signal is a quantized function of the phase difference between clocks.
56 Fascicle III.4 -- Rec. G.701
Note -- In practice this implies that the working range of phase errors is divided into a finite number of subranges and that a unique signal is derived for each subrange whenever the error falls within a subrange.
7015 time quantized control
S: control por cuantificacion´ temporal
A method of controlling clocks in which each clock control signal is derived or utilized only at a number of discrete instants, which may or may not be equally separated in time.
7016 synchronized network [synchronous network]
F: reseau´ synchronise´ [reseau´ synchrone]
S: red sincronizada [red sincrona]
A network in which the corresponding significant instants of nominated signals are adjusted to make them synchronous.
Fascicle III.4 -- Rec. G.701 57
7017 non-synchronized network
F: reseau´ non synchronise´
S: red no sincronizada
A network in which signals need not be synchronous.
7018 mutually synchronized network
S: red mutuamente sincronizada
A synchronized network in which each clock exerts a degree of control on all others.
7019 democratic network, democratic mutually synchronized network
S: red democratica,´ red democratica´ mutuamente sincronizada
A mutually synchronized network in which all clocks are of equal status and exert equal amounts of control on the others; the network operating frequency (digit rate) being the mean of the natural (uncontrolled) frequencies of all the clocks.
7020 hierarchic network, hierarchic synchronized network
S: red jerarquica,´ red con sincronizacion´ jerarquica´
A synchronized network in which each clock is assigned a particular status which determines the degree of control it exerts over the other clocks.
7021 hierarchic mutually synchronized network
S: red jerarquica´ mutuamente sincronizada
A mutually synchronized network in which each clock is assigned a particular status which determines the degree of control it exerts over other clocks; the network operating frequency being a weighted mean of the natural frequencies of all the clocks.
7022 monarchic network, monarchic synchronized network [despotic network, despotic synchronized network]
S: red despotica,´ red con sincronizacion´ despotica´ [red monarquica,´ red con sincronizacion´ monarquica]´
A synchronized network in which a single clock exerts control over all the other clocks.
58 Fascicle III.4 -- Rec. G.701
7023 oligarchic network, oligarchic synchronized network
S: red oligarquica,´ red con sincronizacion´ oligarquica´
A synchronized network in which a few selected clocks are mutually synchronized and exert control over all the other clocks.
|
2.8 8001 |
Pulse Code Modulation pulse code modulation (PCM) |
||||
|
F: S: |
modulation par impulsions et codage (MIC) modulacion´ por impulsos codificados (MIC) |
A process in which a signal is sampled, and each sample is quantized independently of other samples and converted by encoding to a digital signal.
Fascicle III.4 -- Rec. G.701 59
|
8002 |
differential pulse code modulation (DPCM) F: modulation par impulsions et codage differentiel´ (MICD) S: modulacion´ por impulsos codificados diferencial (MICD) A process in which a signal is sampled, and the difference between each sample of this signal and its estimated |
value is quantized and converted by encoding to a digital signal.
Note -- The estimated values of the signal are calculated by a predictor from the quantized difference signal.
8003 delta modulation
F: modulation delta
S: modulacion´ delta
A form of differential pulse code modulation in which only the sign of the difference between each sample and its predicted value is detected and encoded by a single bit.
|
8004 |
adaptive differential pulse code modulation (ADPCM) F: modulation par impulsions et codage differentiel´ adaptatif (MICDA) S: modulacion´ por impulsos y codigo´ diferencial adaptativo (MICDA) A form of differential pulse code modulation that uses adaptive quantizing. Note 1 -- The predictor may be either fixed (time invariant) or variable. Note 2 -- When the predictor is adaptive, the adaption of its coefficients is made from the quantized difference |
signal.
8005 predictor
F: predicteur´
S: predictor
A device that provides an estimated value of a sampled signal derived from previous samples of the same signal or from a quantized version of those samples.
8006 adaptive predictor
F: predicteur´ adaptatif
S: predictor adaptativo
A predictor whose estimating function is made variable according to the short term spectral characteristics of the sampled signal.
8007 sample
F: echantillon´
S: muestra
60 Fascicle III.4 -- Rec. G.701
|
8008 |
A representative value of a signal at a chosen instant, derived from a portion of that signal. sampling F: echantillonnage´ S: muestreo The process of taking samples of a signal, usually at equal time intervals. |
||
|
8009 |
sampling rate F: frequence´ d'echantillonnage´ [taux d'echantillonnage]´ S: velocidad de muestreo [frecuencia de muestreo] The number of samples taken of a signal per unit time. Fascicle III.4 -- Rec. G.701 |
61 |
|
8010 |
F: S: The |
working range plage de fonctionnement [gamme de fonctionnement] gama de funcionamiento range of values of an input signal over which an equipment is designed to operate with a specified |
performance. (See Figure 2/G.701.)
8011 quantizing
F: quantification
S: cuantificacion´
A process in which a continuous range of values is divided into a number of adjacent intervals, and any value within a given interval is represented by a single predetermined value within the interval. (See Figure 2/G.701.)
8012 adaptive quantizing
F: quantification adaptative
S: cuantificacion´ adaptativa
Quantizing in which some parameters are made variable according to the short term statistical characteristics of the quantized signal.
8013 uniform quantizing
F: quantification uniforme
|
S: cuantificacion´ uniforme Quantizing in which all the quantizing intervals lying entirely |
with |
the |
working |
range |
are |
equal. |
(See |
|||||||
|
Figure 2/G.701.) 8014 non-uniform quantizing F: quantification non uniforme S: cuantificacion´ no uniforme |
Quantizing in which not all the quantizing intervals lying entirely with the working range are equal. (See Figure 2/G.701.)
8015 quantizing interval
F: intervalle de quantification
S: intervalo de cuantificacion´
One of the intervals used in quantizing. (See Figure 2/G.701.)
8016 decision value
62 Fascicle III.4 -- Rec. G.701
F: valeur de decision´ [amplitude de decision]´
|
S: valor de decision´ A value defining the boundary between adjacent quantizing intervals. (See Figures 2/G.701 and 4/G.701.) |
||
|
8017 |
virtual decision value F: valeur virtuelle de decision´ [amplitude virtuelle de decision]´ S: valor virtual de decision´ Each of the two defined values, that provide conventional bounds for the working range in quantizing. (See |
Figure 2/G.701.)
Note -- These values are taken to represent hypothetical outer bounds for the two extreme quantizing intervals of the quantizing law.
Fascicle III.4 -- Rec. G.701 63
8018 quantized value
F: valeur quantifiee´ [amplitude quantifiee]´
|
S: valor cuantificado The single discrete value used to represent any value in a particular quantizing interval. (See Figure 2/G.701.) |
||
|
8019 |
load capacity [overload point] F: capacite´ de charge [point de surcharge] S: capacidad de carga [punto de sobrecarga] The level of a sinusoidal signal whose positive and negative peaks coincide with the virtual decision values. |
|
|
8020 |
peak limiting, peak limiting in quantizing F: ecr|´ tage S: limitacion´ de cresta (en cuantificacion)´ The effect whereby any value to be quantized lying outside the working range is replaced by the nearest |
quantized value. (See Figure 2/G.701.)
8021 quantizing distortion
F: distorsion de quantification
|
S: distorsion´ de cuantificacion´ The distortion resulting from the process of quantizing samples within the working range. |
|||
|
8022 |
quantizing distortion power F: puissance de distorsion de quantification S: potencia de la distorsion´ de cuantificacion´ The power of the distortion component of the output signal resulting from the process of quantizing. |
||
|
8023 |
encoding [coding, coding in PCM] F: codage S: codificacion´ [codificacion´ en MIC] The generation of a code word to represent a quantized value. |
||
|
8024 |
encoder [coder] F: codeur S: codificador |
||
|
64 |
Fascicle III.4 -- Rec. G.701 |
|
8025 |
A device that performs encoding. uniform encoding F: codage uniforme S: codificacion´ uniforme The generation of code words to represent uniformly quantized values. |
||
|
8026 |
non-uniform encoding F: codage non uniforme S: codificacion´ no uniforme The generation of code words to represent non-uniformly quantized values. (See Figure 3/G.701.) Fascicle III.4 -- Rec. G.701 65 |
|
8027 |
F: S: The |
encoding law loi de quantification [loi de codage] ley de codificacion´ law defining the relative values |
of the quantizing intervals used in quantizing and encoding. (See |
Figure 4/G.701.)
8028 segmented encoding law
S: ley de codificacion´ por segmentos
An encoding law in which an approximation to a smooth law is obtained by a number of linear segments. (See Figures 3a/G.701 and 3b/G.701.)
8029 decoding
F: decodage´
|
S: decodificacion´ The generation of reconstructed samples. |
||
|
8030 |
decoder F: decodeur´ S: decodificador A device that performs decoding. |
|
|
8031 |
reconstructed sample F: echantillon´ reconstitue´ S: muestra reconstruida The signal generated at the output of a decoder when a specified digital signal representing a quantized value is |
applied to its input.
8032 codec
F: codec
S: codec´
A combination of an encoder and a decoder operating in opposite directions of transmission in the same equipment.
Note -- When used to describe an equipment the function of the equipment should qualify the title, for example: supergroup codec, hypergroup codec.
66 Fascicle III.4 -- Rec. G.701
8033 digilogue channel
F: voie digilogue
S: canal digi-analogico´
A channel in which information is represented by a digital signal at one end and the same information is represented by the corresponding analogue signal at the other end.
Note -- The term may be qualified by ``A to D'' or ``D to A'' to indicate whether encoding or decoding is being performed.
8034 digilogue circuit
F: circuit digilogue
S: circuito digi-analogico´
A circuit in which transmission is provided in one direction by an A to D digilogue channel and in the other direction by a D to A digilogue channel.
Note -- Because the digital interface is inherently 4-wire, the term may be qualified by ``2-W'' or ``4-W'' to indicate whether the analogue interface is 2-wire or 4-wire.
Fascicle III.4 -- Rec. G.701 67
|
Figure 2/G.701, p. Figure 3/G.701, p. |
68 Fascicle III.4 -- Rec. G.701
|
2.9 9001 |
Codes pulse code |
Figure 4/G.701, p. |
||||
|
F: S: |
code d'impulsions (code de modulation d'impulsions) codigo´ de impulsos |
|
A set of rules giving the equivalence between each quantized value and its corresponding code word. |
||
|
9002 |
line code F: code en ligne S: codigo´ de linea,´ codigo´ en linea´ A code chosen to suit the characteristics of a channel, that defines the equivalence between sets of digits |
presented for transmission and the corresponding sequence of signal elements transmitted over that channel.
9003 redundant line code
F: code en ligne redondant
S: codigo´ de linea´ redundante
A line code that uses more encoded signal elements than strictly necessary to represent groups of digits of the original signal.
9004 alternate mark inversion code (AMI code)
F: code bipolaire [code bipolaire alternant, code bipolaire strict]
Fascicle III.4 -- Rec. G.701 69
S: codigo de inversion´ de marcas alternada (codigo AMI) [codigo´ bipolar]
A line code that employs a ternary signal to convey binary digits, in which successive binary ones are represented by signal elements that are normally of alternating, positive and negative polarity but equal in amplitude, and in which binary zeros are represented by signal elements that have zero amplitude.
70 Fascicle III.4 -- Rec. G.701
9005 modified alternate mark inversion code
F: code bipolaire alternant modifie´
S: codigo´ de inversion´ de marcas alternada modificado
A line code that is based on an alternate mark inversion code, in which alternate mark inversion violations occur in accordance with a defined set of rules.
9006 alternate mark inversion signal [bipolar signal]
|
F: signal bipolaire [signal bipolaire alternant] S: sen~ al de inversion´ de marcas alternada [sen~ al bipolar] |
||
|
The encoded signal produced by alternate mark inversion code. |
||
|
9007 |
alternate mark inversion violation [bipolar violation] F: violation de bipolarite´ S: violacion´ de inversion´ de marcas alternada [violacion´ bipolar] A non-zero signal element in an alternate mark inversion signal that has the same polarity as the previous |
non-zero signal element.
9008 disparity
F: disparite´
S: disparidad
The algebraic sum of the values of the departure from notional zero level of one or more consecutive signal elements forming a defined group.
9009 digital sum
F: somme numerique´
|
S: suma digital The algebraic sum of the disparities of a sequence of consecutive defined groups of signal elements. |
||
|
9010 |
digital sum variation F: variation de la somme numerique´ S: variacion´ de la suma digital The difference between the maximum possible digital sum and the minimum possible digital sum of a specified |
number of groups of signal elements.
9011 balanced code
Fascicle III.4 -- Rec. G.701 71
S: codigo´ equilibrado
A code that generates only groups of signal elements that have zero digital sum.
9012 paired-disparity code [alternate code, alternating code]
S: codigo´ con disparidad compensada [codigo´ alternado, codigo´ alternante]
A code in which some or all of the digits in the original signal are represented by two assemblies of digits, of opposite disparity, which are used in a sequence to minimize the digital sum of a longer sequence of digits.
Note -- An alternate mark inversion signal is an example of a paired-disparity code.
72 Fascicle III.4 -- Rec. G.701
9013 PCM binary code
F: code binaire MIC
|
S: codigo´ binario MIC A pulse code in which all the quantized values are identified by binary numbers taken in order. Note -- This term should not be used for line transmission. |
||
|
9014 |
symmetrical binary code F: code binaire symetrique´ S: codigo´ binario simetrico´ A pulse code in which the sign of the quantized value, is represented by one digit, and in which the remaining digit |
constitute a binary number representing the magnitude.
Note 1 -- In a particular symmetrical binary code, the order of the digits and the use made of the symbols 0 and 1 in the various digit positions must be specified.
|
Note 2 -- This term should not be used for line transmission. |
|||
|
9015 |
code conversion F: transcodage S: conversion´ de codigo´ The conversion of digital signals in one code to the corresponding signals in a different code. Alphabetical list of terms defined in this Recommendation |
||
|
8004 8006 8012 3023 9012 9004 9012 9006 9007 7014 |
adaptive differential pulse code modulation (ADPCM) adaptive predictor adaptive quantizing alarm indication signal (AIS) [alternate code] alternate mark inversion code (AMI code) [alternating code] alternate mark inversion signal alternate mark inversion violation amplitude quantized control Fascicle III.4 -- Rec. G.701 |
73 |
|
7012 1002 6015 6018 9011 7011 2003 2002 9006 9007 3019 5003 4001 6022 1005 4002 6006 2005 1007 6009 7004 2005 8032 8024 8023 6021 6023 2026 2020 2019 8016 8030 8029 8003 74 |
analogue analogue anisochronous [asynchronous/heterochronous] balanced bilateral binary binary [bipolar [bipolar bit sequence bunched (bus: centralized-clock channel, channel channel [character circuit, clock clock code codec [coder] [coding, codirectional contradirectional controlled decision decision decision decoder decoding delta Fascicle |
analogue control analogue signal anisochronous [asynchronous/heterochronous] balanced code bilateral control binary digit binary figure [bipolar signal] [bipolar violation] bit sequence independence bunched frame alignment signal (bus: American) centralized-clock interface channel, transmission channel channel gate channel time-slot [character signal] circuit, telecommunication circuit clock clock control signal code word codec [coder] [coding, coding in PCM] codirectional interface contradirectional interface controlled slip decision circuit decision instant, decision instant of a digital signal decision value decoder decoding delta modulation III.4 -- Rec. G.701 |
|
7019 2029 4011 7022 8002 8033 8034 2001 2008 2013 3020 6005 4019 3002 3003 3004 4016 4015 3006 2030 4021 3013 3013 3012 3015 3005 4014 4017 4003 4013 4021 3005 3017 3017 |
democratic network, democratic mutually synchronized network descrambler (deserializer: American) [despotic network, despotic synchronized network] differential pulse code modulation (DPCM) digilogue channel digilogue circuit digit digit position digit rate digit sequence integrity digit time-slot digital block digital channel, digital transmission channel digital circuit, digital telecommunication circuit digital connection digital demultiplexer digital demultiplexing digital distribution frame digital error digital filling digital line link [digital line path] digital line section digital line system digital link, digital transmission link digital multiplexer digital multiplex equipment digital multiplex hierarchy digital multiplexing [digital padding] [digital path] digital radio link [digital radio path] Fascicle |
III.4 -- Rec. G.701 75 |
|
3016 3018 3007 2006 9009 9010 3003 3001 3002 3005 3014 3022 4005 1003 9008 5004 7009 4010 3009 3011 3010 8024 8023 8027 2015 2016 2030 2032 2033 2031 2031 2034 4007 5001 76 |
digital digital digital digital digital digital digital digital digital digital digital digital (digroup: discretely-timed disparity distributed double-ended [dynamicizer] elementary elementary elementary encoder encoding encoding equivalent equivalent error, error error [error error error frame frame Fascicle |
digital radio section digital radio system digital section digital signal digital sum digital sum variation digital telecommunication circuit digital transmission digital transmission channel digital transmission link digital transmission system digital transparency (digroup: American) discretely-timed signal disparity distributed frame alignment signal double-ended synchronization [dynamicizer] elementary cable section elementary regenerator section elementary repeater section encoder encoding encoding law equivalent binary content equivalent bit rate error, digital error error multiplication error multiplication factor [error rate] error ratio error spread frame frame alignment III.4 -- Rec. G.701 |
|
5002 5005 6008 6020 7021 7020 4001 6017 3025 1008 6014 2024 4026 4022 4029 4032 4028 4027 9002 2014 7013 8019 6011 4031 4031 6016 9005 7022 4008 7018 4006 2009 4024 4024 |
frame alignment signal frame alignment recovery time frame alignment time-slot heterochronous hierarchic mutually synchronized network hierarchic network, hierarchic synchronized network highway homochronous [housekeeping digits] interface isochronous jitter justifiable digit time-slot justification justification rate justification ratio justification service digit justifying digit line code line digit rate linear analogue control load capacity master clock maximum justification rate [maximum stuffing rate] [mesochronous] modified alternate mark inversion code monarchic network, monarchic synchronized network multiframe mutually synchronized network n-ary digital group n-ary digital signal negative justification [negative stuffing, negative pulse stuffing] |
Fascicle III.4 -- Rec. G.701 77 |
|
4030 4033 4030 4033 7017 6018 8026 8014 2004 3021 7023 5006 8019 9012 4010 4018 8020 6019 4023 4023 4025 4025 4025 8005 4005 4004 4005 2012 9001 8001 4022 8018 8011 8021 78 |
nominal nominal [nominal [nominal non-synchronized non-synchronous non-unifrom non-uniform octet octet oligarchic out-of-frame [overload paired-disparity parallel PCM peak plesiochronous positive [positive positive/zero/negative [positive/zero/negative positive/zero/negative predictor [primary primary primary psuedo pulse pulse [pulse quantized quantizing quantizing Fascicle |
nominal justification rate nominal justification ratio [nominal stuffing rate] [nominal stuffing ratio] non-synchronized network non-synchronous non-unifrom encoding non-uniform quantizing octet octet sequence integrity oligarchic network, oligarchic synchronized network out-of-frame alignment time [overload point] paired-disparity code parallel to serial converter PCM multiplex equipment peak limiting, peak limiting in quantizing plesiochronous positive justification [positive stuffing, positive pulse stuffing] positive/zero/negative justification [positive/zero/negative stuffing] positive/zero/negative pulse stuffing predictor [primary block] primary digital group primary PCM group psuedo n-ary signal pulse code pulse code modulation (PCM) [pulse stuffing] quantized value quantizing quantizing distortion III.4 -- Rec. G.701 |
|
8022 8015 8031 2010 9003 2011 6010 2021 2023 2022 3011 3009 6013 6003 8007 8008 8009 2028 3008 8028 4011 4010 3025 1001 2007 6007 2017 7008 2026 4011 4026 4022 4027 4029 |
quantizing distortion power quantizing interval reconstructed sample redundant digital signal redundant line code redundant n-ary signal reference clock regeneration regenerative repeater regenerator [regenerator section] [repeater section] relative time interval error retiming sample sampling sampling rate scrambler section termination segmented encoding law serial to parallel converter (serializer: American) service digits signal signal element signalling time-slot significant instant, significant instant of a digital signal single-ended synchronization [slip] [staticizer] [stuffable digit time-slot] [stuffing] [stuffing digit] [stuffing rate] |
Fascicle III.4 -- Rec. G.701 79 |
|
4032 4028 4009 2014 9014 7001 7003 7006 7005 7007 6016 7016 7016 1006 1007 4012 6012 7015 6004 6002 7002 6001 6002 1004 1005 4020 3022 2027 8025 8013 7010 2018 3024 8017 80 |
[stuffing [stuffing subframe [symbol symmetrical synchronization synchronization synchronization synchronization synchronization synchronous synchronized [synchronous telecommunication telecommunication time-division time time time-slot [timing timing timing timing transmission tranmission transmultiplexer transparency, uncontrolled uniform uniform unilateral unit upstream virtual Fascicle |
[stuffing ratio] [stuffing service digit] subframe [symbol rate] symmetrical binary code synchronization synchronization information synchronization link synchronization node synchronization network synchronous synchronized network [synchronous network] telecommunication telecommunication circuit time-division multiplexing time interval error time quantized control time-slot [timing extraction] timing information timing signal timing recovery transmission tranmission channel transmultiplexer transparency, digital transparency uncontrolled slip uniform encoding uniform quantizing unilateral control unit interval upstream failure indication virtual decision value III.4 -- Rec. G.701 |
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2025 8010 |
wander working range Reference |
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[1] |
CCITT Recommendation Definitions relating to national and international numbering plans , Vol. VI, Fascicle III.4 -- Rec. G.701 81 |
DIGITAL HIERARCHY BIT RATES
(Malaga-Torremolinos, 1984; amended at Melbourne, 1988)
The CCITT,
considering
(a) that digital hierarchy bit rates are those bit rates which are or will be used as the basis for higher digital hierarchy levels if such levels exist (see Recommendation G.701, definition 4003);
(b) that the specification of hierarchical bit rates is necessary to prevent the proliferation of interface standards used in digital networks;
(c) that international interconnections of digital network components are preferably carried out at hierarchical bit rates;
(d) that when determining hierarchical bit rates a number of factors relating to services, transmission media and networking need to be taken into account, for example:
|
-- -- -- -- -- |
characteristics of and suitable coding method for analogue source signals; bit rates of digital source signals; use of available transmission media; compatibility with analogue multiplex systems; modularity and flexibility in assembling and routing groups of source signals, |
recommends
|
that the following bit rates should be used as hierarchical bit rates in digital networks: |
Table [T1.702], p. |
Figure 1/G.702 and Figure 2/G.702 show the recommended hierarchical bit rates only, including references to related Recommendations on network interfaces, multiplex equipments, digital sections/systems.
82 Fascicle III.4 -- Rec. G.702
Recommendations on the following may also exist, but are not identified in Figure 1/G.702 and Figure 2/G.702: -- multiplex equipments operating between non-adjacent levels of the digital hierarchy;
-- network interfaces, multiplex equipments and digital sections/systems at non-hierarchical bit rates.
Annex A to this Recommendation provides guidelines on usable bit rates available for services.
Fascicle III.4 -- Rec. G.702 83
Figure 1/G.702, p. 84 Fascicle III.4 -- Rec. G.702
Figure 2/G.702, p. Fascicle III.4 -- Rec. G.702 85
ANNEX A
(to Recommendation G.702)
Usable bit rates available for services
In the case of access to the ISDN for broadband services, bit rates up to the primary hierarchy level are specified in the I.200 series of Recommendations.
In general, with regard to bit rates available for transport of service signals, the following guidelines apply:
A.1 For the hierarchies based on the 1544 kbit/s primary rate, the principle has been established that some bits in the frame should be reserved, in particular to perform quality control of the digital paths when several digital sections in tandem are involved. Table A-1/G.702 provides the necessary information.
Table A-1/G.702 [T2.702], p.
A.2 In case of networks using 2048 kbit/s based hierarchy there is in principle no basic restriction on the use of full capacity of the digital path. However, it is recognized that compatibility with recommended frame structures at the various levels of the 2 Mbit/s hierarchy (e.g. the use of the same frame alignment pattern) could be a preferred solution since it offers the following advantages:
-- use of the same framing devices for switched and non-switched applications;
-- end-to-end quality control performed in a unique way by the network when the maintenance entity that terminates the service (e.g. the encoding device) does not belong to the network;
-- possibility of performing additional network management functions that could be required, depending on the applications.
The preference for compatibility with recommended frame structures could be reconsidered for the applications where significant restrictions on the efficient use of the digital path capability can be identified.
86 Fascicle III.4 -- Rec. G.702
Fascicle III.4 -- Rec. G.702 87