I have two buildings, about 10 minutes apart, that share the same phone system and SIP trunk. One is large with about 70 phones and the other very small with only 2 phones.
Our telco set us up with a SIP trial when I was getting the phones ready to use. There was one DID with this, which was used to register with the SIP server. I realized during installation that since the phones at both locations share the same SIP trunk to the outside world, the addresses coming into 911 would all be the same - that of our main building. Thought of a solution rather fast though - simply re-use the DID from our SIP trial (ending in 1060) and have the phones at the remote site send this as their caller ID. All the rest of the phones at the main site would send our primary phone number ending in 4411. (I’m going to use these 4-digit numbers throughout the rest of this message for brevity & privacy; I have the full 10-digit DID in the system itself.)
Unfortunately, things have not worked as smoothly as planned, which you probably already know given that I’m posting in the forums about it.
If I make test calls to my cell phone from our main site, the caller ID comes through correctly with 4411. If I call my cell from the remote site, it comes through with the 1060 number. Everything is working perfectly! I place a test call to 911 … … … and they get 1060 no matter which site I call from.
The engineer at the SIP provider assures me that they send out whatever caller ID is sent by the PBX to 911 as long as that number is on our account, which both are. I have set 4411 in both the default route and the outbound route for 911, at the extension level as the caller ID, and as the emergency caller ID in the extension. It works for non-emergency calls, but doesn’t matter for emergency calls though - they still only receive 1060 as the caller ID no matter what I do. The telco engineer found the SIP session of my latest test call to 911 and sure enough, it shows 1060 in the FROM field, even though it’s set to be 4411 in all these locations.
I’m really at a loss of what to do next. All I really need is to get every phone in the system to outpulse 4411 to 911 except for 2 that would outpulse 1060, exactly the same as they do for calls to a cell phone. It’s kind of important to get this functional as if there’s an emergency at the remote site, we don’t want them coming to the main site first.