Standards History
CCIR CCITT General International
International Secretariat Frequency
Radio Telegraph and Registration
Consultative Telephone Board
Committee Consultative (IFRB)
Committee
CCITT study groups
| COM I | Definition, operation and quality of service aspects of |
| telegraph, data transmission and telematic services | |
| COM II | Operation of telephone network and ISDN |
| COM III | General tariff principles including accounting |
| COM IV | Transmission maintenance of international lines, circuits and chains of circuits; maintenance of automatic and semi-automatic networks |
| COM V | Protection against dangers and disturbances of electromagnetic origin |
| COM VI | Outside plant |
| COM VII | Data communication networks |
| COM VIII | Terminal equipment for telematic services |
| COM IX | Telegraph networks and terminal equipment |
| COM X | Languages and methods for telecommunications applications |
| COM XI | ISDN and telephone network switching and signaling |
| COM XII | Transmission performance of telephone networks and terminals |
| COM XV | Transmission systems |
| COM XVII | Data transmission over the telephone network |
| COM XVIII | Digital networks including ISDN |
4 - Standards
The nature of packet switching means that the customers terminal (computer)
equipment is deeply involved with the procedures for setting up calls, error
correction and all aspects of running the link, the customers equipment almost
becoming part of the network.
Such networks only become practical when there is a commonly accepted standard
for the orderly exchange of data (known as the protocol)
The widely used standard for packet switching is known as X.25, this is defined
by the CCITT (Consultative Committee International Telephony & Telegraphy).
X.25 is not specific enough in some parts and different packet switching networks
and different suppliers of computer equipment sometimes interpret it differently.
The types of customers equipment which can be connected to an X.25 link into
Public Network range from small microprocessor PADs to large mainframe computers
(PAD = Packet Assembler/Dissesembler
- described in Public Network-PAD).
CCITT standards available from:
International Telecommunication Union
CCITT standards
The X-series Recommendations, Volume VIII, are published in the Red Book
they can be ordered from
CCITT
Sales Services
ITU
Place des Nations,
CH-1211,
Geneva 20,
Switzerland
Volume VIII consists of the following seven fascicles:
VIII.1 Data communication over the telephone network.
Series V Recommendations
VIII.2 Data communications networks: services and facilities
Recommendations X.1 - X.15
VIII.3 Data communications networks: interfaces
Recommendations X.20 - X.32
VIII.4 Data communications networks: transmission, signaling and
switching, network aspects, maintenance and administrative
arrangements.
Recommendations X.40 - X.181
VIII.5 Data communications networks: Open Systems Interconnection (OSI),
system description techniques
Recommendations X.200 - X.250
VIII.6 Data communications networks: interworking between networks,
mobile data transmission systems
Recommendations X.300 - X.353
VIII.7 Data communications networks: Message Handling Systems
Recommendations X.400 - X.430
X series - applicable to public data networks.
| X.1 | international user classes of service in public data networks |
| X.2 | international user facilities in public data networks. |
| X.3 | Packet assembly/disassembly |
| X.4 | General structure of signals of IA5 code for data transmission over public data networks |
| X.20 | Interface between data terminal equipment and data circuit- terminating equipment for start-stop transmission services on public data networks. |
| X20 bis | V21 compatible interface between DTE and DCE for start-stop transmission services on public data networks. |
| X.21 | General purpose interface between DTE and DCE for synchronous operation on public data networks. |
| X21 bis | use on public data networks of DTE which are designed for interfacing to synchronous V-series modems. |
| X22 | Multiplex DTE/DCE Interface for user classes 3-6 |
| X24 | list of definitions of interchange circuits between DTE and DCE on public data networks |
| X.25 | Interface between DTE and DCE for terminals operating in packet mode on public data networks. |
| X.26 | Electrical characteristics for unbalanced double-current interchange circuits for general use with integrated circuit equipment in the field of data communications (identical to V10) |
| X.27 | (identical to V.11) |
| X.28 | DTE/DCE interface for a start/stop mode DTE accessing the PAD facility on a public data network situated in the same country. |
| X.29 | Procedures for exchange of control information and user data between a packet mode DTE and a PAD |
| X.30 | Support of X.21 and X.21bis based DTE's on the ISDN |
| X.31 | Support of packet mode terminal equipment's on an ISDN |
| X.32 | Interface between DTE and DCE for packet-mode terminals accessing a packet switched public data network through a public switched telephone network of a circuit switched public data network. |
| X.40 | Standardization of frequency shift modulated transmission systems for the provision of telegraph and data channels by frequency division of a primary group |
| X.50 | Fundamental parameters of a multiplexing scheme for the international interface between synchronous data networks |
| X.51bis | |
| X.52 | |
| X.53 | |
| X.54 | |
| X.60 | |
| X.61 | |
| X.70 | |
| X.71 | |
| X.75 | Terminal and transit call control procedures to data transfer on international circuits between public data networks operating in the packet mode. |
| X.80 | |
| X.87 | |
| X.92 | hypothetical reference connections for public synchronous data networks |
| X.95 | NETWORK parameters in public data networks |
| X.96 | call progress signals in public data networks. |
| X.101 | See X.150 |
| X.110 | Routing principles for international public data services through switched public data networks of the same type. |
| X.121 | International numbering plan for public data networks. |
| X.130 | |
| X.150 | DTE and DCE test loops for public data networks for X.21 for X.21bis interfaces (was X.101) |
| X.180 | Administration arrangements for international closed user groups. |
| X.200 | reference model of OSI |
| X.210 | Layer service conventions of OSI for CCITT applications |
| X.211 | Physical Layer service definition of OSI for CCITT applications |
| X.212 | Data link layer service definition of OSI for CCITT applications |
| X.213 | Network service definition of open systems Interconnection for CCITT applications. |
| X.214 | (ISO DP 8072) Transport service of OSI |
| X.215 | session layer service definition |
| X.216 | Presentation Layer service definition of OSI for CCITT applications |
| X.217 | Common application service elements definition of OSI for CCITT applications |
| X.224 | (ISO DP 8073) Transport protocol specifications of open systems interconnection for CCITT applications. |
| X.225 | session protocol specification |
| X.300 | General principles and arrangement for interworking between public data networks, and between public data networks and other public networks. |
message handling systems
| X.400 | system model - service elements |
| X.401 | basic service elements and optional user facilities |
| X.408 | encoded information type conversion rules |
| X.409 | presentation transfer syntax and notation |
| X.410 | remote operations and reliable transfer server |
| X.411 | message transfer layer |
| X.420 | Inter=personal messaging user agent layer |
| X.430 | access protocol for teletex terminals |
| F.200 | The teletex service |
| S.60 | Teletex terminal equipment |
| S.61 | Character sets and coding for teletex |
| S.62 | contol procedures for Teletex and Group 4 Facsimile |
| S.70 | The teletex transport service |
ISO standards
Information processing systems - open systems interconnection
| ISO 3309 | HDLC |
| ISO DP 7498 | Basic reference model (was ISO TC97/SC16 N227) |
| ISO DP 8326 | Session Services |
| ISO DP 8072 | Transport service definition |
| 646 | 7-bit coded character set for information processing exchange. (IS) |
| 963 | Guide for the definition of the 4-bit character set for information processing exchange. (IS) |
| 2014 | Writing of calendar dates in all numeric form. (IS) |
| 2022 | Code extension technique for use with the 7-bit coded character set. (IS) |
| 2382/8 | Information processing - vocabulary - data communications. (IS) |
| 2382/18 | Information exchange - vocabulary - distributed data processing. (IS) |
| 3307 | Information Interchange - representation of time of day. (IS) |
| 3309 | HDLC - Unbalanced class of procedures. (IS) |
| 4073 | 8-bit coded character set for information interchange. (IS) |
| 4335 | HDLC - Balanced class of procedures. (IS) |
| 6093 | Representation of numeric values in character strings for information interchange. (IS) |
| 6429 | Additional control functions for character imaging devices. |
| 7498 | OSI - Basic reference model. (IS) (same as CCITT X200) |
| - dad 1: Connectionless mode. (ISO 8524). | |
| - dad 2: Naming and addressing. | |
| 7776 | HDLC - X25 link access procedures (1984 compatible). |
| 8072 | OSI - Transport service definition. (S) |
| - dad 1: Connectionless transport service. | |
| 8073 | OSI - Connection oriented transport protocol. (IS) |
| - dad 1: Connectionless transport protocol. | |
| - dad 2: Network connection management (network addressing). | |
| 8208 | X25 - Packet mode protocol (1984 compatible). |
| 8326 | OSI - Connection oriented session service. (IS) |
| - dad 1: Symmetric synchronisation. | |
| 8327 | OSI - Connection oriented session protocol. (IS) |
| - dad 1: Symmetric synchronisation. | |
| 8348 | OSI - Network service definition. |
| - dad 1: Connectionless network service. | |
| - dad 2: Network layer addressing. | |
| 8471 | HDLC - Consolidation of elements of procedures. |
| 8472 | OSI - Network convergence protocol. |
| [For X25(1980); superseded by ISO 8878] | |
| OSI - Connectionless network service protocl. | |
| 8509 | OSI - Service conventions. |
| 8524 | OSI - Reference model - connectionless mode addendum. |
| 8571 | OSI - File transfer, access and manipulation (FTAM). |
| 8571/1 - General description. | |
| 8571/2 - Virtual file store. | |
| 8571/4 - File protocol specification. | |
| 8602 | OSI - Connectionless transport protocol. |
| 8649 | OSI - Common application service elements (CASE). |
| 8649/1 - Introduction. | |
| 8649/2 - Basic kernel subset. | |
| 8649/3 - Commitment, concurrency and recovery (CCR). | |
| 8650 | OSI - Protocols for common application service elements(In several parts; 8650/3 covers CCR). |
| 8802 | IEEE 802 compatible standards 8802/1 to 8802/5. (e.g. 8802/2 OSI - Data link layer). |
| 8802/7 | Slotted ring technique (i.e. Cambridge ring R-layer). |
| 8807 | LOTOS - A formal description technique. |
| 8822 | OSI - Connection oriented presentation service. |
| 8823 | OSI - Connection oriented presentation protocol. |
| 8824 | OSI - Specification of abstract syntax notation one ASN.1). |
| 8831 | OSI - Job transfer and manipulation (JTM) service. |
| 8832 | OSI - JTM basic class protocol |
| 8871 | OSI - Data link layer address resolution. |
| 8878 | OSI - Use of X25(1984) to provide connection oriented NS. |
| 8880/1 General issues. | |
| 8880/2 In relation to X25(1984). | |
| 8880/3 In relation to ISO 8473. | |
| 8882 | X25 DTE conformance testing. |
| 8885 | General-purpose XID I-field content and format. |
| 8886 | OSI - Data link service. |
| 9065/60 | Message oriented text interchange. |
| 9074 | ESTELLE - a formal description technique |
