Whats the difference between G.729a and G.711?
G.711 and G.729a are both standards-based voice codecs (encoder-decoders) that take the voice signal and compress it for transmission across the Internet. G.711 (or PCM) is the ‘granddaddy’ of codecs and has been used on the traditional telephone network for years. It provides excellent call quality with minimum compression at the expense of using more bandwidth (typically around 80 kbps per channel). G.729a is much more highly-compressed and offers slightly-reduced call quality in return for a significant reduction in bandwidth usage (typically 10 Kbps per channel). Because of the extra compression, G.729a will consume more CPU power per channel than G.711. The codec used is negotiated between the calling and called party’s hardware. If a called user’s hardware device or VoIP provider only supports one codec then this is the codec that will be used. Keyfonics supports the above mentioned codecs plus G.723, G.726 and GSM but virtually all modern IP phones will support at minimum G.711
