G729 License Key

Does it really help to reduce traffic load?
Do I need one for every channel or just per provider?
and where can I get or buy this license?

g.729 reduces bandwidth usage from 64kbit/sec (ulaw/alaw) (which becomes about 80kbit/sec with overhead) per channel to under 10kbit/sec (around 20kbit/sec with overhead).
You must buy one license for each channel you want to use the 729 codec on. Remember that the license key includes the number of licenses so if you want to put five channels on each of two machines, order 2 5-channel keys instead of 10 channels. If you order 10 channels you will get a 10channel key that only works on one machine.

Also if you don’t want to pay for channel licenses many providers support alternate codecs like g.726, iLBC, GSM, etc. However g.729 is by far the best supported low-bit codec among phones.


Yes 28K instead of 80K per call

You need one for every call that is Transcoded


I’ve read that there are open sources implementations of it, how does that work? and does anyone know anything about it?

Yes there are ‘open source’ implementations available, but that doesn’t get you off the hook for paying.
See the entanglement for g.729 is not a piece of proprietary code that can be written around but rather a patent on the method used to encode things (as I understand it at least). There are ‘free’ implementations available (see the voip-info.org page on g.729) but they may not be legally used in the USA and many other countries except for research and debugging purposes. If you live in a country that does not recognize USA Intellectual Property laws, then you may freely use this codec. Otherwise, you must pay Digium for the number of channels you will use.

no worries, I’m about to buy an 8 license key… it’s cheap enough…

cool. good luck with your project!