E911 CER call flow

System Version: 8.7.1.10000-17
what is the call flow?
I am tring to understand how this works, we have several "outreach" clinics and they are not giving the PSAP the correct call back number.

Here is my understanding of the flow.
A 911 call is made, UCM routes that call to the CER/e911 system then that outputs the "call back" number from the ERL
The ERL number sends the programmed number to "our" gateway then the gateway sends the number to the carrier then the carrier routes the call to the PSAP.

Sounds simple enough
but the PSAP is not getting the number programmed on the ERL.
So does the carrier provide the PSAP with information we give them once they see the number we are sending or should they just be sending what we are giving them to the PSAP?

it seems that each vendor is pointing the finger at the other vendor and they don't want to talk to each other, sound familar.
Anyway, any help of information on how this works is greatly appreaciated.

 

[whykap]

Run a q931 debug on the gateway the call is going out. Monitor a 911 call and see if the caller ID send out is the correct one (the one the ERL provides). If it is then the issue is with your provider overwriting your caller ID.
If it is not the correct number then CER and CUCM is not properly configured.

 

[MitelInMyBlood]

This "finger pointing" is exactly why we chose to go with a total turnkey E911 solution from a single-source vendor who specializes in 911 systems.

I suspect, as whykap suggested, that the problem may be with your external phone service provider.

I'm unfamiliar with CER, but conceivably you should be able to perform a number transformation on the trunk to send your 911 test calls to a regular POTS line equipped with a CallerID display, in order to see exactly what's going on. There are also some diagnostics available on your gateway router, but actually seeing what pops up in callerID can maybe get you pointed in the right direction (as to who is really at fault).



Original MUG/NAMU Charter Member

 

[watchdovr]

thanks guys, I am currently trying to get with the "correct" department now, with the carrier, to verify what they are recieving and the information they are sending.
It appears that we are correctly sending the information that corrisponds with the location but are the 911 is still getting the incorrect return phone number.
I'll keep you posted