Emergency Responder

[belz-e]

I am a little confused on the use of ELIN's. If we are sending the ANI in the caller ID of the phone initiating the 911 call to the PSAP and the PSAP is seeing the orginal calling number of the phone then why is there a need for the ELIN? Can someone clarify this for me. And also is the ELIN required? I know when setting up the ERL's it does not require the field to be filled in.

Thanks,

Erik

[Chris Deren]

You need the ELIN so you can do the coordination between the ELIN number and location. For example if you dial from a particular phone how would the PSPA know if it's 3rd floor of a building. You submit the ELIN - location mapping to your PSAP this way they know the exact location of the caller. ELIN info is only required for multi tenant buildings and buildings over 40,000 sq ft. Otherwise you don't even need CER, unless for example your phones are not DIDs, then CER will still route the PSAP callback back to the original phone that dialed 911.

Chris

[belz-e]

ok. I understand your methodology but lets look at it here for a moment. we create an ERL we assign all the ALI data to the ERL. We then assign the phones to that ERL and export the database to NENA format and send to LEC. Should that database not contain the phone to ERL mapping? The phones have external phone number masking and are passing these to the LEC through PRI so the actually caller ID(ANI) of the phone is seen by the PSAP. If not and then the ELIN is the route to go.. Do I use the calling party modification feature pick arbitrary DID numbers and assign them as ELIN's to the ERL's? So for instance I have a building with 36 floors each floor gets its own ERL. I have a DID block of 408326XXXX should I just pick 36 ordinary DID's out of that block for ELIN's.

Thanks,

Erik

[MarkMonteleone]

Having similar quagmire, have small ISP rolling out voip (IPCentrex) solutions and find myself unaware of the potenial issues.

Please advise

[j.sillers]

It is my understanding that the 911 services do not look at CallerID. The info passed by the Telco Switch includes the PRI main identifier which is located in seperate fields from the CID info. So in an IP Centrex solution you may need a 1:1 ration of DID to ERL's and ELIN's which would then be imported into the Telco database.