This Technical Reference (TR) contains the Telcordia view of generic requirements for User-to-User Signaling (UUS) in an Integrated
Services Digital Network (ISDN). User-to-User Signaling with Call Control (UUSCC) is a service that allows user equipment to exchange
user information in the Call Request phase, Call Confirmation phase, and/or in the Call Clearing phase of a call. This feature is
applicable for point-to-point, on-demand, circuit-switched, and packet-mode calls. Although UUSCC is both a circuit-switched and
packet-mode feature, the Signaling System Number 7 (SS7) procedures only support the circuit-switched operation of UUSCC.
This document contains Supplement 1, dated April, 1990, and Bulletin 1, dated April, 1992.
Supplement 1 provides information necessary to obtain compatible ISDN.
Bulletin 1 announces the intention of Telcordia to revise the generic requirements in the document for the interswitch indication
that UUS information has been discarded by the network. Currently, the document specifies that when UUS information is discarded by
the network, it shall be indicated by the inclusion of the cause indicators parameter with cause value 43, "access information
discarded (diagnostic: User-to-User Indicators (UUI) parameter)," in the SS7 ISDN User Part (ISDNUP) Call Progress Message (CPG) in
cases where no interworking is encountered. The revision will replace the use of the cause indicators parameter for this purpose by
the User-to-User Indicators Parameter (UUIP).
The use of the SS7 cause indicators parameter has become obsolete in both CCITT and ANSI standards and has been replaced by the
UUIP. The procedures for when interworking is encountered and the Q.931 procedures are not affected by these changes.