The ITU-T V-Series Recommendations on Data communication over the telephone network specify the protocols that govern approved modem communication standards and interfaces.[1]

General standardsApplies to V.1–V.9

V.1 is an ITU-T recommendation, entitled Equivalence between binary notation symbols and the significant conditions of a two-condition code.

V.2 is an ITU-T recommendation, approved in November 1988, titled Power levels for data transmission over telephone lines. V.4 is an ITU-T recommendation, approved in November 1988, titled General structure of signals of International Alphabet No. 5 code for

character oriented data transmission over public telephone networks. V.5 was an ITU-T recommendation, approved in November 1988, titled Standardization of data signalling rates for synchronous data

transmission in the general switched telephone network. It has been withdrawn since. V.6 was an ITU-T recommendation, approved in November 1988, titled Standardization of data signalling rates for synchronous data

transmission on leased telephone-type circuits. It has been withdrawn since. V.7 is an ITU-T recommendation, approved in November 1988, titled Definitions of terms concerning data communication over the

telephone network. V.8 is an ITU-T recommendation, first approved in September 1994, titled Procedures for starting sessions of data transmission over the

public switched telephone network. It has been superseded three times. The current version was approved in November 2000. V.8bis is an ITU-T recommendation, first approved in August 1996, titled Procedures for the identification and selection of common modes

of operation between data circuit-terminating equipments (DCEs) and between data terminal equipments (DTEs) over the public switched telephone network and on leased point-to-point telephone-type circuits. It has been superseded twice. The current version was approved in November 2000.

Interfaces and voiceband modems

Applies to V.10–V.34

V.10 is a ITU-T recommendation, first agreed in 1976, for unbalanced electrical circuits for data communication at up to 100 kbit/s. It can interwork with V.28, provided it is not exposed to signals greater than 12 volts. Used with the 37-pin ISO 4902 connector, it is compatible with EIA RS423.

V.11 is an ITU-T recommendation, first agreed in 1976, for balanced electrical circuits for data communication at up to 10 Mbit/s. Used with the 37-pin ISO 4902 connector, it is compatible with EIA RS-422. The 15-pin ISO 4903 connector is recommended for data network interface.

V.17 is an ITU-T fax protocol that uses TCM modulation at 12 and 14.4 kbit/s. V.21 is an ITU-T recommendation for full-duplex communication between two analogue dial-up modems using audio frequency-shift

keying modulation at 300 baud to carry digital data at 300 bit/s. It is a variant of the original Bell 103 modulation format. V.22 is an ITU-T recommendation for full-duplex communication between two analogue dial-up modems using PSK modulation at 600

baud to carry data at 1200 or 600 bit/s. It is a variant of the Bell 212A modulation format. V.22bis is an ITU-T recommendation extending V.22 with a faster rate using QAM modulation at 600 baud to carry digital data at 2400 or

1200 bit/s. The 1200 bit/s mode is compatible with V.22. V.23 is an ITU-T recommendation for half-duplex communication between two analogue dial-up modems using FSK modulation at up to

600 or 1200 baud to carry digital data at up to 600 or 1200 bit/s respectively. An optional 75 baud reverse channel carries 75 bit/s. V.24 is referenced as RS-232. V.250 (also known as V.25ter) is extended data modems ITU-T recommendation .[2]

V.27ter is an ITU-T recommendation for a half-duplex modem, allowing 2400 and 4800 bit/s (PSK modulation). V.28 is an ITU-T recommendation defining the electrical characteristics for unbalanced double-current interchange circuits. V.29 is an ITU-T recommendation for a modem, allowing 4.8 kbit/s, 7.2 kbit/s and 9.6 kbit/s transfer modes (PSK and QAM modulations). V.32 is an ITU-T recommendation for a modem operating as full-duplex on a 4-wire circuit, or half-duplex on a two-wire circuit, allowing

bidirectional data transfer at either 9.6 kbit/s or 4.8 kbit/s at a symbol rate of 2,400 baud instead of the 600 baud of the V.22 standards. V.32bis is an ITU-T recommendation for a modem, allowing up to 14.4 kbit/s bidirectional data transfer. Other additional defined data

transfer rates are 12.0 kbit/s, 9.6 kbit/s, 7.2 kbit/s, and 4.8 kbit/s. The standard was extended by several modem manufacturers to allow bidirectional data transfer rates of 19.2 kbit/s, but never ratified as a V.32ter standard. These non-ITU-T standard modems were often referred to as 'V.32terbo' modems.[3]

V.33 is an ITU-T recommendation for a modem operating as full-duplex on a 4-wire point-to-point leased line allowing bidirectional data transfer at either 14.4 kbit/s.

V.34 (09/94) is an ITU-T recommendation (superseded) for a modem, allowing up to 28.8 kbit/s bidirectional data transfer. Other additional defined data transfer rates are 24.0 kbit/s and 19.2 kbit/s as well as all the permitted V.32 and V.32bis rates. It is the successor to the unofficial V.FC (V.Fast Class; also known as V34draft) standard created by Hayes and Rockwell, which was the first widely available 28.8 kbit/s protocol. Most V.34 modems support V.FC, although not all modern modems support both. Additionally V. 34 modems employs shell mapping as shaping code to reduce the transmit power.

V.34 (10/96) is an updated ITU-T recommendation for a modem, building on the V.34 standard but allowing up to 33.6 kbit/s bidirectional data transfer. Other additional defined data transfer rates are 31.2 kbit/s, as well as all the permitted V.34 rates. Sometimes called V.34+, but this was never an official name. It was later superseded by V.34 (02/98) which corrected some errata in the original 1996 document.

Wideband modems

Applies to V.35–V.39

V.35 is an ITU-T standard located on layer 1 on the OSI model. Max speed is 2 Mbit/s. Withdrawn ITU-T recommendation for 48 kbit/s data transmission over wideband circuits. The physical and electrical characteristics of this interface are now specified in ITU-T recommendation V.11.

Error control and data compression

Applies to V.40–V.49

V.41 is a code-independent error control system. Defines the ITU-T standard CRC-16 polynomial as x16 + x12 + x5 + 1 V.42 is an error correction protocol. Its function is to allow the receiver to immediately request re-transmission of any lost data packets.

However, it does not guarantee how quickly the error-free data will be delivered to the receiving end. V.42 is generally included in dialup modems. Also defines the ITU-T standard CRC-32 polynomial as x32+x26+x23+x22+x16+x12+x11+x10+x8+x7+x5+x4+x2+x+1, and includes the LAPM framing protocol.

V.42bis also an adaptive data compression standard, based on the Lempel Ziv dynamic dictionary approach, and may go to "transparent mode," in which data is transmitted uncompressed. The specific algorithm is "BTLZ" (British Telecom Lempel Ziv), which was developed by Alan Clark (then with BT, later CTO of Hayes).

V.44 is an based on LZJH (Lempel-Ziv-Jeff-Heath) adaptive data compression developed by Hughes Electronics for its DirecPC satellite Internet, and incorporated into the v.92 dial-up modem standard. V.44 offers somewhat better compression performance for certain types of data than the V.42bis standard, on average allowing 15% greater throughput. For instance, a 53.3 kbit/s connection with V.44 can transmit up to 53.3×6 = 320 kbit/s using pure text. In reality, the overall data rate rarely exceeds 3:1 compression (~150 kbit/s). It should be noted that the compression tends to get better and worse over time due to noise on the line, or due to the transfer of already-compressed files (ZIP files, JPEG images, MP3 audio, MPEG video). At some points the modem will be sending compressed files at 53 kbit/s, uncompressed files at 160 kbit/s, and pure text at 320 kbit/s, or any value in between. [4][5]

Simultaneous transmission of data and other signals

Applies to V.60–V.99

V.61 Analog Simultaneous Voice and Data (ASVD) V.70 Digital Simultaneous Voice and Data (DSVD) V.80: videoconferencing. It is generally compatibilized with H.324 standard point-to-point video telephony over regular phone lines. V.90 is an ITU-T recommendation for a modem, allowing 56 kbit/s download and 33.6 kbit/s upload. It replaced two vendor standards

(K56flex and X2) and was designed to allow modems from both prior standards to be flash upgraded to support it. It was developed between March 1998 and February 1999. It is also known as V.Last as it was anticipated to be the last standard for modems operating near the channel capacity of POTS lines to be developed. V.90 is generally used in concert with the V.42bis compression standard. A follow-on standard, V.92, was developed later in 1999 to replace V.90.

V.92 is an ITU-T recommendation, titled Enhancements to Recommendation V.90, that establishes a modem standard allowing 56 kbit/s download, 48 kbit/s upload rates, and the new V.44 compression method. V.92 was first presented in August 1999. It is intended to succeed the V.90 standards. With V.92, PCM is used for both the upstream and downstream connections; previously 56K modems only used PCM for downstream data.

Interworking with other networks

Applies to V.100–V.199

V.110 is an ITU-T recommendation for using terminal adaptor functions for the connection of terminals having interfaces conforming to V-series to the ISDN.

V.120 is an extension for V.110 that includes statistical multiplexing. V.150.1 is an ITU-T recommendation for using a modem over IP networks.

Interface layer specifications for data communication

Applies to V.200–V.249

V.230 is an ITU-T recommendation, approved in November 1988, titled General data communications interface layer 1 specification.

Control procedures

Applies to V.250–V.299

Digital circuit modems

Applies to V.300–V.399

  

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A seriesD seriesE seriesF seriesG seriesH seriesI seriesJ seriesK seriesL seriesM seriesN seriesO seriesP seriesQ seriesR seriesS seriesT seriesU seriesV seriesX seriesY seriesZ series

X series: Data networks, open system communications and securityX.1-X.199 : Public data networksX.1-X.19 : Services and facilitiesX.20-X.49 : InterfacesX.20: Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for start-stop transmission services on public data networksX.20 bis: Use on public data networks of Data Terminal Equipment (DTE) which is designed for interfacing to asynchronous duplex V-Series modemsX.21: Interface between Data Terminal Equipment and Data Circuit-terminating Equipment for synchronous operation on public data networksX.21 bis: Use on public data networks of Data Terminal Equipment (DTE) which is designed for interfacing to synchronous V-Series modemsX.22: Multiplex DTE/DCE interface for user classes 3-6X.24: List of definitions for interchange circuits between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) on public data networksX.25: Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode and connected to public data networks by dedicated circuitX.26/V.10: Electrical characteristics for unbalanced double-current interchange circuits operating at data signalling rates nominally up to 100 kbit/sX.27/V.11: Electrical characteristics for balanced double-current interchange circuits operating at data signalling rates up to 10 Mbit/sX.28: DTE/DCE interface for a start-stop mode Data Terminal Equipment accessing the Packet Assembly/Disassembly facility (PAD) in a public data network situated in the same countryX.29: Procedures for the exchange of control information and user data between a Packet Assembly/Disassembly (PAD) facility and a packet mode DTE or another PADX.30/I.461: Support of X.21, X.21 bis and X.20 bis based Data Terminal Equipments (DTEs) by an Integrated Services Digital Network (ISDN)X.31/I.462: Support of packet mode terminal equipment by an ISDNX.32: Interface between Data terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode and accessing a Packet-Switched Public Data Network through a public switched telephone network or an Integrated Services Digital Network or a Circuit-Switched Public Data NetworkX.33: Access to packet-switched data transmission services via frame relaying data transmission servicesX.34: Access to packet-switched data transmission services via B-ISDNX.35: Interface between a PSPDN and a private PSDN which is based on X.25 procedures and enhancements to define a gateway function that is provided in the PSPDNX.36: Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment

(DCE) for public data networks providing frame relay data transmission service by dedicated circuitX.37: Encapsulation in X.25 packets of various protocols including frame relayX.38: G3 facsimile equipment/DCE interface for G3 facsimile equipment accessing the Facsimile Packet Assembly/Disassembly facility (FPAD) in a public data network situated in the same countryX.39: Procedures for the exchange of control information and user data between a Facsimile Packet Assembly/Disassembly (FPAD) facility and a packet mode Data Terminal Equipment (DTE) or another FPADX.42: Procedures and methods for accessing a public data network from a DTE operating under control of a generalized polling protocolX.45: Interface between data terminal equipment (DTE) and data circuit-terminating equipment (DCE) for terminals operating in the packet mode and connected to public data networks, designed for efficiency at higher speedsX.46: Access to FRDTS via B-ISDNX.48: Procedures for the provision of a basic multicast service for data terminal equipments (DTEs) using Recommendation X.25X.49: Procedures for the provision of an extended multicast service for data terminal equipments (DTEs) using Recommendation X.25X.50-X.89 : Transmission, signalling and switchingX.90-X.149 : Network aspectsX.150-X.179 : MaintenanceX.180-X.199 : Administrative arrangementsX.200-X.299 : Open Systems InterconnectionX.200-X.209 : Model and notationX.210-X.219 : Service definitionsX.220-X.229 : Connection-mode protocol specificationsX.230-X.239 : Connectionless-mode protocol specificationsX.240-X.259 : PICS proformasX.260-X.269 : Protocol IdentificationX.270-X.279 : Security ProtocolsX.280-X.289 : Layer Managed ObjectsX.290-X.299 : Conformance testingX.300-X.399 : Interworking between networksX.300-X.349 : GeneralX.350-X.369 : Satellite data transmission systemsX.370-X.379 : IP-based networksX.400-X.499 : Message Handling SystemsX.600-X.629 : NetworkingX.630-X.639 : EfficiencyX.640-X.649 : Quality of serviceX.650-X.679 : Naming, Addressing and RegistrationX.680-X.699 : Abstract Syntax Notation One (ASN.1)X.700-X.799 : OSI managementX.700-X.709 : Systems management framework and architectureX.710-X.719 : Management communication service and protocolX.720-X.729 : Structure of management informationX.730-X.799 : Management functions and ODMA functions

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Provisional name

A seriesD seriesE seriesF seriesG seriesH seriesI seriesJ seriesK seriesL seriesM seriesN seriesO seriesP seriesQ series

Q series: Switching and signallingQ.1-Q.3 : Signalling in the international manual serviceQ.1: Signal receivers for manual workingQ.2: Signal receivers for automatic and semi-automatic working, used for manual workingQ.4-Q.59 : International automatic and semi-automatic workingQ.4-Q.9 : Basic RecommendationsQ.10-Q.11 : Numbering plan and dialling procedures in the international serviceQ.11 bis/E.164/I.331: The international public telecommunication numbering planQ.12-Q.19 : Routing plan for international serviceQ.20-Q.34 : General Recommendations relative to signalling and switching systems (national or international)Q.35-Q.39 : Tones for use in national signalling systemsQ.40-Q.47 : General characteristics for international telephone connections and circuitsQ.48-Q.49 : Signalling for satellite systems

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R seriesS seriesT seriesU seriesV seriesX seriesY seriesZ series

Q.50-Q.59 : Signalling for circuit multiplication equipmentQ.60-Q.99 : Functions and information flows for services in the ISDNQ.60-Q.67 : MethodologyQ.68-Q.79 : Basic servicesQ.80-Q.99 : Supplementary servicesQ.100-Q.119 : Clauses applicable to ITU-T standard systemsQ.100-Q.109 : General clausesQ.110-Q.114 : Transmission clauses for signallingQ.110: General aspects of the utilization of standardized CCITT signalling systems on PCM linksQ.112: Signal levels and signal receiver sensitivityQ.113: Connection of signal receivers in the circuitQ.114: Typical transmission requirements for signal senders and receiversQ.115-Q.115 : Logic and protocols for the control of signal processing network elements and functionsQ.116-Q.119 : Abnormal conditionsQ.120-Q.499 : Specifications of Signalling Systems No. 4, 5, 6, R1 and R2Q.120-Q.139: Specifications of Signalling system No. 4Q.120: Definition and function of signalsQ.121: Signal codeQ.122: Signal senderQ.123: Signal receiverQ.124: Splitting arrangementsQ.125: Speed of switching in international exchangesQ.126: Analysis and transfer of digital informationQ.127: Release of registersQ.128: Switching to speech positionQ.129: Maximum duration of a blocking signalQ.130: Special arrangements in case of failures in the sequence of signalsQ.131: Abnormal release conditions of the outgoing register causing release of the international circuitQ.133: Numbering for access to automatic measuring and testing devicesQ.134: Routine testing of equipment (local maintenance)Q.135: Principles of rapid transmission testing equipmentQ.136: Loop transmission measurementsQ.137: Automatic testing equipmentQ.138: Instruments for checking equipment and measuring signalsQ.139: Manual testingQ.140-Q.180: Specifications of Signalling System No. 5Q.140: Definition and function of signalsQ.141: Signal code for line signallingQ.142: Double seizing with both-way operationQ.143: Line signal senderQ.144: Line signal receiverQ.145: Splitting arrangementsQ.146: Speed of switching in international exchangesQ.151: Signal code for register signallingQ.152: End-of-pulsing conditions – Register arrangements concerning ST (end-of-pulsing) signalQ.153: Multifrequency signal sender

Q.154: Multifrequency signal receiverQ.155: Analysis of digital information for routingQ.156: Release of international registersQ.157: Switching to the speech positionQ.161: General arrangements for manual testingQ.162: Routine testing of equipment (local maintenance)Q.163: Manual testingQ.164: Testing equipment for checking equipment and signalsQ.180: Interworking of signalling systems No. 4 and No. 5Q.251-Q.300: Specifications of Signalling System No. 6Q.251: GeneralQ.252: Signal transfer time definitionsQ.253: Association between signalling and speech networksQ.254: Telephone signalsQ.255: Signalling-system-control signalsQ.256: Management signalsQ.257: GeneralQ.258: Telephone signalsQ.259: Signalling-system-control signalsQ.260: Management signalsQ.261: Normal call set-upQ.262: Analysis of digital information for routingQ.263: Double seizing with both-way operationQ.264: Potential for automatic repeat attempt and re-routingQ.265: Speed of switching and signal transfer in international exchangesQ.454: The sending part of the multifrequency signalling equipmentQ.455: The receiving part of the multifrequency equipmentQ.457: Range of interregister signallingQ.458: Reliability of interregister signallingQ.460: Normal call set-up procedures for international workingQ.462: Signalling between the outgoing international R2 register and an incoming R2 register in an international exchangeQ.463: Signalling between the outgoing international R2 register and an incoming R2 register in a national exchange in the destination countryQ.464: Signalling between the outgoing international R2 register and the last incoming R2 registerQ.465: Particular casesQ.466: Supervision and release of the callQ.468: Routing and numbering for international workingQ.470: Termination of interregister signalling at an incoming R2 register situated in a transit exchangeQ.471: Termination of interregister signalling at the last incoming R2 register situated in the exchange to which the called subscriber is connectedQ.472: Termination of interregister signalling at the last incoming R2 register situated in a transit exchangeQ.473: Use of end-of-pulsing signal I-15 in international workingQ.474: Use of group B signalsQ.475: Normal release of outgoing and incoming R2 registersQ.476: Abnormal release of outgoing and incoming R2 registers

  

 

A seriesD seriesE seriesF seriesG seriesH seriesI seriesJ seriesK seriesL seriesM seriesN seriesO seriesP seriesQ seriesR seriesS seriesT seriesU seriesV seriesX seriesY seriesZ series

G series: Transmission systems and media, digital systems and networksG.100-G.199 : International telephone connections and circuitsG.100-G.109 : Transmission planning and the E-modelG.100/P.10: Vocabulary for performance and quality of serviceG.100.1: The use of the decibel and of relative levels in speechband telecommunicationsG.101: The transmission planG.102: Transmission performance objectives and RecommendationsG.103: Hypothetical reference connectionsG.105: Hypothetical reference connection for crosstalk studiesG.107: The E-model: a computational model for use in transmission planningG.108: Application of the E-model: A planning guideG.108.1: Guidance for assessing conversational speech transmission quality effects not covered by the E-modelG.108.2: Transmission planning aspects of echo cancellersG.109: Definition of categories of speech transmission qualityG.110-G.119 : General Recommendations on the transmission quality for an entire international telephone connectionG.120-G.129 : General characteristics of national systems forming part of international connectionsG.130-G.139 : General characteristics of the 4-wire chain formed by the international circuits and national extension circuitsG.140-G.149 : General characteristics of the 4-wire chain of international circuits; international transitG.150-G.159 : General characteristics of international telephone circuits and national extension circuitsG.160-G.169 : Apparatus associated with long-distance telephone circuitsG.170-G.179 : Transmission plan aspects of special circuits and connections using the international telephone connection network

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G.180-G.189 : Protection and restoration of transmission systemsG.190-G.199 : Software tools for transmission systemsG.440-G.449 : Circuit noiseG.450-G.499 : Coordination of radiotelephony and line telephonyG.450-G.469 : Radiotelephone circuitsG.470-G.499 : Links with mobile stationsG.600-G.699 : Transmission media and optical systems characteristicsG.600-G.609 : GeneralG.610-G.619 : Symmetric cable pairsG.620-G.629 : Land coaxial cable pairsG.630-G.639 : Submarine cablesG.640-G.649 : Free space optical systemsG.650-G.659 : Optical fibre cablesG.660-G.679 : Characteristics of optical components and subsystemsG.680-G.699 : Characteristics of optical systemsG.700-G.799 : Digital terminal equipmentsG.700-G.709 : GeneralG.710-G.729 : Coding of voice and audio signalsG.730-G.739 : Principal characteristics of primary multiplex equipmentG.740-G.749 : Principal characteristics of second order multiplex equipmentG.750-G.759 : Principal characteristics of higher order multiplex equipmentG.760-G.769 : Principal characteristics of transcoder and digital multiplication equipmentG.770-G.779 : Operations, administration and maintenance features of transmission equipment

 

 

   

 

A seriesD seriesE seriesF seriesG seriesH seriesI seriesJ seriesK seriesL seriesM seriesN seriesO seriesP seriesQ seriesR seriesS seriesT series

I series: Integrated services digital networkI.100-I.199 : General structureI.110-I.119 : TerminologyI.120-I.129 : Description of ISDNsI.130-I.139 : General modelling methodsI.140-I.149 : Telecommunication network and service attributesI.150-I.199 : General description of asynchronous transfer modeI.200-I.299 : Service capabilitiesI.200-I.209 : ScopeI.210-I.219 : General aspects of services in ISDNI.220-I.229 : Common aspects of services in the ISDNI.230-I.239 : Bearer services supported by an ISDNI.240-I.249 : Teleservices supported by an ISDNI.250-I.259 : Supplementary services in ISDNI.300-I.399 : Overall network aspects and functionsI.310-I.319 : Network functional principlesI.320-I.329 : Reference models

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U seriesV seriesX seriesY seriesZ series

I.330-I.339 : Numbering, addressing and routingI.340-I.349 : Connection typesI.350-I.359 : Performance objectivesI.360-I.369 : Protocol layer requirementsI.370-I.399 : General network requirements and functionsI.400-I.499 : ISDN user-network interfacesI.410-I.429 : Application of I-series Recommendations to ISDN user-network interfacesI.410: General aspects and principles relating to Recommendations on ISDN user-network interfacesI.411: ISDN user-network interfaces – Reference configurationsI.412: ISDN user-network interfaces – Interface structures and access capabilitiesI.413: B-ISDN user-network interfaceI.414: Overview of Recommendations on layer 1 for ISDN and B-ISDN customer accessesI.420: Basic user-network interfaceI.421: Primary rate user-network interfaceI.430-I.439 : Layer 1 RecommendationsI.440-I.449 : Layer 2 RecommendationsI.450-I.459 : Layer 3 RecommendationsI.460-I.469 : Multiplexing, rate adaption and support of existing interfacesI.470-I.489 : Aspects of ISDN affecting terminal requirementsI.500-I.599 : Internetwork interfacesI.500: General structure of the ISDN interworking RecommendationsI.501: Service interworkingI.510: Definitions and general principles for ISDN interworkingI.511: ISDN-to-ISDN layer 1 internetwork interfaceI.515: Parameter exchange for ISDN interworkingI.520: General arrangements for network interworking between ISDNsI.525: Interworking between networks operating at bit rates less than 64 kbit/s with 64 kbit/s-based ISDN and B-ISDNI.530: Network interworking between an ISDN and a public switched telephone network (PSTN)I.540/X.321: General arrangements for interworking between Circuit-Switched Public Data Networks (CSPDNs) and Integrated Services Digital Networks (ISDNs) for the provision of data transmission servicesI.550/X.325: General arrangements for interworking between Packet-Switched Public Data Networks (PSPDNs) and Integrated Services Digital Networks (ISDNs) for the provision of data transmission servicesI.555: Frame Relaying Bearer Service interworkingI.560/U.202: Technical requirements to be met in providing the international telex service within an integrated services digital networkI.570: Public/private ISDN interworkingI.571: Connection of VSAT based private networks to the public ISDNI.572: VSAT interconnection with the PSTNI.580: General arrangements for interworking between B-ISDN and 64 kbit/s based ISDNI.581: General arrangements for B-ISDN interworkingI.600-I.699 : Maintenance principlesI.601: General maintenance principles of ISDN subscriber access and subscriber installationI.610: B-ISDN operation and maintenance principles and functionsI.630: ATM protection switchingI.700-I.799 : B-ISDN equipment aspectsI.730-I.739 : ATM equipment

I.740-I.749 : Transport functionsI.750-I.759 : Management of ATM equipmentI.760-I.769 : Multiplexing aspectsI supplements : Supplements to the Series I RecommendationsI Suppl. 1: Generic service descriptions for ten supplementary services defined in I.250-Series Recommendations

 

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