sosoft cantata voice/data codec
A variety of different forms of audio codec or vocoder are available for general use, and the GSM system supports a number of specific audio codecs. These include the RPE-LPC, half rate, and AMR codecs. The performance of each voice codec is different and they may be used under different conditions, although the AMR codec is now the most widely used.
Also the newer AMR wideband (AMR-WB) codec is being introduced into many areas, including GSMVoice codec technology has advanced by considerable degrees in recent years as a result of the increasing processing power available. This has meant that the voice codecs used in the GSM system have large improvements since the first GSM phones were introduced.