If I have a g.729 license for 2 channels, and a 3 call goes

If I have a g.729 license for 2 channels, and a 3 call goes out what happens? Does it use fallback and use ulaw (g.711)?

I have 2 lines that will be in use regularly and there may be a very rare occasion when a 3 line is in use at the same time.


always by more licences than you think you will need. they are only $10 each. some calls will use more than 1 licence, for example if you are recording calls.


Oh, seriously? Recording calls takes two licenses?

In the event all the channels are used up, does it just not work at all then? Like the person calling will trigger a no channel available error?


The call will fail. Asterisk doesn’t know that a G.729 decoder/encoder isn’t available until it actually goes to use one… meaning when the RTP stream begins. This happens after the call is set up at the SIP level, so the session will initiate properly, but no audio will flow.

If recording is going to be a big component of your application and you don’t want to purchase extra licenses, there is a workaround you could implement. If you dump both channels into a MeetMe conference you can record the conference without requiring an extra G.729 license. MeetMe transcodes everything to s-linear, so the recording doesn’t require a license to write a WAV file.

So if I don’t do the MeetMe work around what is the general rule of thumb of how many extra I should have?

IE. If I think I need 10, get 12, if I’m going to record everything, make it 24?

That sounds about right… They are only $10/ea, so it isn’t too painful to get some extras.