scope:

The present document defines the mapping functions in exchanges of Private Integrated Services Networks (PISNs) required for the utilization of scenarios in which 64 kbit/s circuit mode connections are sub-multiplexed into 4 ´ 16 kbit/s channels for carrying inter-Private Integrated services Network eXchange (PINX) signalling and user information.

NOTE: The present document has been prepared to meet the specific needs of an application for a particular user organization. However, it may also be applicable elsewhere. The requirements contained in the present document will be incorporated in any future standard specifying a more generic approach to bearer conditioning.

In order to connect a PINX to another PINX, mapping functions are required to adapt the specific interfaces at the C reference point to the application at the Q reference point. As such, mapping functions provide for physical adaptation to the interface at the C reference point. Mapping functions also provide for the mapping of user channels and signalling information at the Q reference point to the appropriate channels or timeslots at the C reference point.

The C and Q reference points are defined in ISO/IEC 11579-1 [1].

The type of interface at the C reference point covered by the present document is the 64 kbit/s digital unrestricted leased line (D64U) terminal equipment interface, in accordance with ETS 300 290 [2].

At the Q reference point the mapping provides a 16 kbit/s service for user channels to support the transfer of unrestricted digital information and to support the transfer of speech, and a packet mode service for the signalling channel. The applied mapping is a static mapping, i.e. there is a fixed relationship between user and signalling channels at the Q reference point and the interface at the C reference point.

Management functions relating to failure management are outside the scope of the present document.

The present document is applicable to PINXs that can be interconnected to form a PISN and that support signalling protocols at the Q reference point