But they do support ULAW, ILBC, SPEEX, GSM, and ADPCM… So which do you recommend?
ulaw if you have the bandwidth, gsm if you don’t. then find another provider that does support g729
i THINK adpcm is g.726 but I could be wrong, if I’m thinking of the right hting it takes up about half the bandwidth of ulaw.
GSM as i recall is around 15k/sec, iLBC as i recall is just under that but uses a ton of CPU power.
As for which to use, use whichever one your phone supports. If Asterisk doesn’t have to transcode that will reduce latency and CPU load. If you must transcode use GSM as it’s easy to transcode to.
Change ISPs ,There are lots of ITSPs that do support g729 on their GWs…
AXVOICE, Iconnecthere and Broadvoice… Each has their shortcomings, that is why I use 2 different ITSP with a SIP trunk to each…To say nothing of the T.38 support… Depending on the plan you select, it can be a fairly economical solution…
In order of Priority for me;
Speex G.722 wide band CoDec (Quality with this can be fantastic and low Bandwidth utilization over some of the others out there).
To be honest with you i am not a big fan of G.729 anyway, i find it to be a little over rated, but that is just my Opinion anyway.