Inbound Calls Fail - NEC SL1100 Adminstrators Manual

BT Wholesale
9.4

Inbound Calls Fail

 Check that the Device is registered as above.
 Check that the SIP/RTP ports are not being blocked by a firewall on the network. Details of the
ports can be found in the Security Guide under Support Centre
Information.
 Check whether any calls can be made between extensions on the PBX; if not they the issue is
likely to be local to the PBX.
 Check that the device is receiving SIP messaging for calls by taking a SIP Protocol Trace and
looking for inbound INVITES within this.
 Check that the expected outbound CLI of either the Trunk Group or the Trunk User is being
presented in the TO header of the inbound SIP INVITE.
 If the Trunk Group or Trunk User DDI's are being received make sure that they match the
format of the numbers in your DDI / DID Table i.e. 441234567890.
 If the DDI / DID Table is correct for the inbound INVITE make sure that the destination for the
call is available to other extensions on the PBX.
 If none of the above points highlight the cause please take a SIP trace of a call failing where
possible and raise a ticket with Support.
Issue 1: 2012© British Telecommunications plc
IN STRICTEST CONFIDENCE
Downloads General Help &
» »
Page 33 of 33
IN STRICTEST CONFIDENCE