Outbound Calls Fail - NEC SL1100 Adminstrators Manual

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9.3

Outbound 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 sending out SIP messaging for calls by taking a SIP Protocol Trace and
looking for outbound INVITES within this.
 Check that the INVITE's are not being continually challenged by the Registrar with 401
responses; if they are then check the SIP Networking Authentication Information details are
the same as those set in the Business Portal.
 Check that the expected outbound CLI of either the Trunk Group or the Trunk User is being
presented in either the From or the P-Asserted-Identity in the outbound SIP INVITE.
 If the Trunk Group or Trunk User DDI's are being sent out in the INVITE make sure that they are
in the correct format i.e. 441234567890.
 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
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