Many times when setting up the Adtran Total Access 900 Series VoIP Gateway the customer will ask me to force a specific Caller ID for 911.
This way even if the PBX sets a different Caller ID when the emergency call goes out the call will still be routed to the local PSAP.
At first I configured it as follows:
voice trunk T01 type sip
match dnis “911” replace ani “2125551212” name “Emergency”
This worked fine until one customer had a their PBX misconfigured by their vendor and certain calls had no Caller ID.
When this happened and 911 was called the Caller ID was not set with the above rule.
It seems that the Gateway only manipulates the SIP Header when there is value to replace; in this case since there was none it skipped the rule.
I found settings below that can fix this.
For 911 calls only you can use the following:
voice trunk T01 type sip
caller-id-override emergency-outbound 2125551212
The setting “emergency-outbound” is hard coded for 911 calls. If your area has a different emergency number or you want to override none 911 calls with no Caller ID you need to use the if-no-cpn option:
voice trunk T01 type sip
caller-id-override number-inbound 2125551212 if-no-cpn
match dnis “911” replace ani “2125551212” name “Emergency”
VoIP4EA 