I tried emailing Digium and all I got was worthless answers like “Purchase as many as you want”. What I want to know is how many licenses do I need? My setup:
6 phones
Digium TDMxxx card (business land line and home land line)
VoIP provider account
Do I need a license, 1 per phone, or 1 per line, or 1 per server, or what?
Does your VoIP provider use g729? If so, how many concurrent calls are you going to be making to that provider? Buy that many licenses.
Tom
I use Teliax and they do support g729 and they allow up to 4 concurrent calls with the plan I’m on. I don’t think I’ve ever used more than 2 at a time so far. If I purchase 2 licenses and for some very odd reason I have 3 concurrent calls, will the 3rd call drop back to ulaw/alaw/gsm or will it error out somehow. If it just drops back, that would be great!
You need to tell your system to use both g729 and whatever other codecs Teliax supports. If you have two g729 connections going and Teliax will handle gsm/ulaw/alaw you’ll get whatever is next in the list in your sip.conf.
Tom
It will drop back if the career supports some of the allowed codecs. Also if your phones are sending the signal in g.729 and you don’t use licenses (translation, monitoring) asterisk would just pass through the calls and won’t use any license.
don’t forget that if you’re using monitoring, chanspy, anything that requires a codec (depends on the format the “channel-addon” is using), you’ll double the number you need. 1 for the leg to your provider, 1 for the leg to your phone.
i have about 10 users hooked up at home, and have 20 licences … not yet had to worry about numbers, and 200 bucks was a lot cheaper than the additional bandwidth over a year.
and of course, you’re giving some revenue to Digium as a kind of thank-you for Asterisk 
who said i was feeling guilty about using Sangoma hardware ???