BS ISO/IEC 8480:1995 Information technology. Telecommunications and information exchange between systems. DTE/DCE interface back-up control operation using ITU-T Recommendation V.24 interchange circuits
Printed version of this is available at library. To request, please e-mail to referencepk@usm.my and include a copy of this record in your e-mail.
This International Standard specifies the procedures for back-up operation applicable to data transmission on a leased line when implemented through a single interface, controlling both the leased and the back-up facilities, using ITU-T Recommendation V.24 interchange circuits in conjunction with either the 25-pole connector (ISO 2110) or the 26-pole connector (ISO/IEC 11569).
The method used to switch the transmission of data automatically from the leased line to or from the back-up facility is not specified in this International Standard.
This International Standard is not applicable where back-up (calling or answering) is achieved by manual means.
NOTES
1 The procedures specified in this International Standard may be used at the answering end only, the calling end only, or both ends of a connection.
2 An ordinary DCE (i.e. one not implementing back-up control) may be provided at either end of the back-up circuit and only for back-up purposes. For example, a calling station could provide one or more separate auto-dial GSTN lines to provide back-up on demand to a greater number of leased lines.
Where data transmission is provided on a leased line, there may be a requirement to provide back-up operation, to be brought into use whenever transmission via the leased line is, for any reason, not possible.
There are several possible back-up facilities:
- back-up of a 2-wire leased line by one GSTN line;
- back-up of a 4-wire leased line by one GSTN line;
- back-up of a 4-wire leased line by two GSTN lines;
- back-up of a 2-wire/4-wire leased line by one/two lines of a private switched network;
- back-up of a 2-wire leased line by one ISDN line, using a terminal adaptor1 ;
- back-up of a 4-wire leased line by one ISDN line, using a terminal adaptor1.
NOTES
1 - This list may not be exhaustive.
2 - the terminal adaptor may be separate equipment or physically combined with the DCE.
The variety of facilities should not be visible in the protocol used at the DTE/DCE interface to exchange the interface control and status information necessary for back-up control. To achieve this, a standardised approach to the required protocol is essential. The majority of applications are, however, restricted to the first two of the listed possibilities. In consequence, this international Standard describes the protocol requirements where only one back-up facility is provided as the alternative to data transmission on the leased line. For other arrangements of facilities, although this International Standard is not directly applicable, it nevertheless should be used as a guide to the protocol requirements.
ICS 35.200 Interface and interconnection equipment
Language:
English
Subject Keywords:
Interfaces (data processing); Teleprocessing; Information exchange; Computer terminals; Data transfer; Communication procedures; Data transmission; Multiplexing; Telephone lines; Telecommunication; Data circuit-terminating equipment; Telephone networks; Computer networks; Data transmission control procedures
BS ISO/IEC 8480:1995 Information technology. Telecommunications and information exchange between systems. DTE/DCE interface back-up control operation using ITU-T Recommendation V.24 interchange circuits
