ISDN Protocol Administrator's and Developer's Guide ... - Intervoice

Two B-Channel TransferThe Two B-Channel Transfer (TBCT) for a Primary Rate Interface(PRI) is defined in Telcordia specification GR-2865-CORE.For more informationabout specificationGR-2865-CORE, see theTelcordia documentGR-2865-CORE GenericRequirements for ISDNPRI Two B-ChannelTransfer.For more information onthe National ISDN 2 ISDNprotocol, see “NationalISDN-2 Protocol,”Chapter 12.With TBCT, an Omvia Media Server using a National ISDN 2 (NI-2)PRI can request a switch to join two independent calls on the sameswitch on the network.The two calls must be served by the same switch, but can be served bythe same or different PRIs. If two or more PRIs are used, both mustoriginate from the same switch. If the switch accepts the transferrequest, the Omvia Media Server releases both calls, and they areconnected directly at the switch.Transfers can occur during either state:• Alerting (Call is ringing)• Connected (Call is answered)The characteristics of TBCT are shown in Table 3-3.Table 3-3. TBCT Transfer CharacteristicsSpan Type Transfer Type connect UserDLL?T1 Two Line Transfer Yes3-4 ISDN Protocol Administrator’s and Developer’s Guide 60001262, First Edition