GB/T 15123-1994
Information processing-Data communication-DTE/DCE interface back-up control operation using the 25-pole connector (English Version)
- Standard No.
- GB/T 15123-1994
- Language
- Chinese, Available in English version
- Release Date
- 1994
- Published By
- General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
- Status
- 2009-01
- Replace By
- GB/T 15123-2008
- Latest
- GB/T 15123-2008
- Scope
- This standard describes the alternate operation implementation method for data transmission using GB3454 interchangeable circuits and GB/T1512525 pin connectors on leased circuits. This standard addresses the increasing need for the ability to provide backup facilities in situations where data transmission is no longer possible on leased lines. There are several possible backup facilities: one general switched telephone network (GsTN) line as backup for a two-wire leased line; one GSTN line as backup for a four-wire leased line; two GSTN lines as backup for a four-wire leased line; Backup of leased lines; use of one/two private switching network lines as backup for a two-wire/four-wire leased line. Note: Using another one/two leased dedicated lines as a backup for a two-wire/four-wire system leased line is a topic for further research, and not all backup facilities are listed above. This change in facility should not be perceptible in the protocol used to exchange interface control and status information at the DTE/DCE interface. It should be understood that data transmission over a leased line is only replaced by an alternate facility. The agreement does not include the case of manual alternate call and answer. In addition, this standard is only applicable where an interface needs to control leased and backup facilities. This standard does not exclude the use of any method for automatically switching data transmission from leased lines to alternate facilities. In automatic standby switchover, the following cases must be distinguished: The switchover of the standby facility is initiated by the DTE. In this standard, this method is called "direct mode switching"; when DTE authorizes DCE, DCE initiates the switching of backup facilities. In this standard, this method is called "authorization method switching". If the DTE cannot control this facility through the interface, it is allowed to select this mode within the DCE during installation. This standard also distinguishes between answering stations and calling stations. Answering station: In this station, the DCE switches to the backup facility upon receipt of a backup request (such as an incoming call). Calling station: In this station, DCE must send a backup request to the called station (such as requesting the other end to switch to the backup facility). It should be noted that these switching methods can be used on the answering side only, on the calling side only, or at both ends of the connection. These handover methods are also available for simple DCEs (i.e. DCEs not implementing standby control) at one of the two ends of the standby circuit and provided for standby purposes only, e.g. a calling station may provide one or more independent automatic dialing GSTN lines , in order to meet the backup requirements of a larger number of leased lines.
GB/T 15123-1994 history
- 2008 GB/T 15123-2008 Information technology.Telecommunication and information exchange between systems.DTE/DCE interface back-up control operation using GB/T 3454 interchange circuits
- 1994 GB/T 15123-1994 Information processing-Data communication-DTE/DCE interface back-up control operation using the 25-pole connector
