This Standard specifies the service description and control aspects, including functional capabilities and information flows, of standardised circuit-mode bearer services which may be supported by a Private Integrated Services Network (PISN).
This Standard includes the following basic 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.
A PISN shall support at least one of the above three bearer services to conform with this Standard.
The scope of this Standard does not include:
- the negotiation of service at call establishment time,
- the change of service during a call, and
- unidirectional services.
This Standard includes optional procedures for the provision of functions equivalent to the following public ISDN supplementary services: Subaddress and Multiple Subscriber Number.