Hi,
I have a currently running Asterisk 1.6 vanilla installation with 900 users. The customer wants to migrate to FreePBX, but he has Alphanumeric extensions. I’ve surfing around FreePBX Forums and I’m aware this is not possible at this time, but its a very important business opportunity for us. How can I get rid of the extension number validation? We have some php programmers who can get their hands on it.
How many extensions? You can use the SIP trunk module, set type as peer and context=from-internal
This will cause a few issues but they can overcome.
Thanks SkykingOH:
There are 700 extensions, that will possibly grow to 1200 
The reason for using alphanumeric extensions is a workaround for SLA-Shared Line Appereance. The president of the company has 4 IP phones. His extension is 29000, but to register and provision his phones to Asterisk, they use 29000a, 29000b, etc and they all have 29000 as the CallerID. That’s the reason we need to put an extra character.
Ok, I assume then you put them in a ring group?
How many of these SLA groups?
It would be like 100! Perhaps hard to mantain.
Are these 700 extensions on one box?
Yes…One Box.
I’ve currently disabled the extension validation. I’m able to submit alpahumeric extensions, but, i don’t know if that could be an aproach.
you can use alphanumeric sip aliases if that would address your issue.
Each extension requires a numeric extension number but each can have a sip alias which is available for sip uri inbound calls if that would address the issue.