ABSTRACT: Issue 3 of GR-2865, Generic Requirements for ISDN PRI Two B-Channel Transfer, replaces Issue 2.

This document contains the Telcordia view of proposed generic requirements for Two B-Channel Transfer (TBCT) for a Primary Rate Interface (PRI) in an Integrated Services Digital Network (ISDN). This document includes both ISDN access signaling and Common Channel Signaling (CCS) Signaling System No. 7 (SS7) requirements.

TBCT allows a user (controller) on a PRI to request the Stored Program Control Switch (SPCS) to connect two independent calls on the user's interface. If the SPCS accepts the request, that controller is released from the calls and the other two users are directly connected. Billing for the original two calls continues in the same manner as if the transfer had not occurred and the controller of the transfer was still connected to both calls. As an option, TBCT allows for transfer notification to the transferred users.

TBCT differs from transfer for a Basic Rate Interface (BRI) as defined in GR-858 in that TBCT has two B channels in use during the transfer request. TBCT saves the PRI user from double trunking after the transfer is completed by the SPCS.

Issue 3 of GR-2865 updates two items in Section 3.3. One item involves correction of a significant typographical error in Figure 3-6 of Section 3.3.12. The other item involves clarification of requirement R3-93 [69] in Section 3.3.1.1. This requirement involves the coding of the Notification Indicator information element in the NOTIFY message used by the Notification to Controller feature.

As a result, the intent of Issue 3 of GR-2865 is to provide one correction and one clarification to existing generic requirements from Issue 2, and not to introduce any new generic requirements on PRI Two B-Channel Transfer.