Integrated Services Digital Network (ISDN) - Terminal Adaptation Using Statistical Multiplexing
|Publication Date:||1 September 1992|
This standard, based on CCITT Recommendation V.120, describes a protocol intended to be used between two terminal adaptor (TA) functional groups, between two ISDN Terminal (TE1) functional groups, between a TA and a TE1, or between either a TA or TE1 and an Interworking Function (IWF) inside a public or private ISDN. It provides for operation:
- over either Circuit mode or Frame Relay connections;
- using either demand or semi-permanent establishment of communications; and
- over any of the following types of access channel: B, H0, H10, H11 or, additionally, for Frame Relay bearer connections, D. It may also be used with the Multirate Circuit Mode Bearer Service.
This standard also describes how this protocol is related to synchronous and asynchronous interface specifications using the interchange circuits such as defined in Recommendation V.24, EIA/TIA 232-E or EIA/TIA 530-A. It is not intended to be a functional specification for an implementation of any system containing a TE1 or TA functional group. Except as explicitly noted, it is restricted to the definition of the protocol at the user-network interface (reference points S, T or U) and the ISDN-side interface of an interworking function (IWF).
The terminal adaption protocol in this standard may be used in support of three classes of non-ISDN-terminal protocols. These are:
a) Asynchronous (Start/Stop) Protocols, supported using the Protocol Sensitive Asynchronous Mode;
b) Synchronous Protocols using HDLC Frame Format, supported using the Protocol Sensitive Synchronous Mode;
c) Synchronous Protocols, supported using the Bit Transparent mode.
However, the Bit Transparent mode is not suitable for use with Frame Relay connections.