IN STRICTEST CONFIDENCE
BT Wholesale
Issue 1: 2012© British Telecommunications plc
Page 5 of 33
IN STRICTEST CONFIDENCE
8.5 COS ......................................................................................................................................................... 27
8.6 Trunk to Trunk Routing - Optional ............................................................................................................. 28
Trunk to Trunk Transfer ............................................................................................................................................ 28
External Call Forward -COS....................................................................................................................................... 28
Trunk to Trunk Options ............................................................................................................................................ 28
8.7 Dialing Plan ............................................................................................................................................. 29
9 TROUBLESHOOTING AND USEFUL INFORMATION ............................................................. 30
9.1 Checking SIP Messaging To/From the PBX .................................................................................................. 30
9.2 Device Fails to Register ............................................................................................................................ 31
9.3 Outbound Calls Fail .................................................................................................................................. 32
9.4 Inbound Calls Fail ..................................................................................................................................... 33