scope:

This Standard specifies control aspects of standardized circuit mode services which may be supported by Private Telecommunication Networks (PTNs). This Standard contains the Stage 1 and Stage 2 specifications of these services.

Definition of signalling protocols at Stage 3 is guided and constrained by the Stage 1 and Stage 2 specifications , and therefore this Standard is concerned mainly with the control aspects of services. The properties of the user information are described for the different basic services which have to be controlled. Detailed requirements of user information protocols and switching functions are outside the scope of this Standard.

NOTE 1:

The services specified are compatible with the equivalent services specified by CCITT and ETSI for public ISDNs. CCITT specifications of these services are to be found in Recommendations I.220, I.230, I.231 (Stage 1), Q.71 (Stage 2), I.240, and I.241.

This Standard applies to the following bearer services:

- Circuit Mode 64 kbit/s Unrestricted 8 kHz Structured Bearer Service Category;

- Circuit Mode 64 kbit/s 8 kHz Structured Bearer Service Category Usable for Speech Information Transfer;

- Circuit Mode 64 kbit/s 8 kHz Structured Bearer Service Category Usable for 3,1 kHz Audio Information Transfer.

The following Teleservices are supported by these bearer services:

- Telephony Teleservice;

- Teletex Teleservice;

- Telefax 4 Teleservice;

- Videotex Teleservice.

This Standard specifies the dynamic procedures for the support of these Teleservices within a PTN. The definition of these Teleservices is beyond the scope of this Standard.

Negotiation of service at call establishment time and change of service during a call are outside the scope of this Standard.

A Stage 3 Standard shall be in conformance with the Stage 1 and Stage 2 specifications contained in this Standard, if the signalling protocols and equipment behaviour specified in the Stage 3 Standard are capable of being used in a PTN which supports any or all of the basic services specified in this Standard. In particular, the Stage 3 Standards shall be adequate for the support of:

- common aspects of the control of basic services, as seen by the PTN user and the interworking with the ISDN, as specified in clauses 9 and 10;

- the control of the individual basic services specified in clauses 5, 6, 7 and 8;

- the functional entities, functional entity allocations and information flows identified in clauses 12, 13, 14 and 16.