G.729 codec is an audio data compression algorithm for voice that compresses digital voice in packets of 10 milliseconds duration. Standard G.711 calls take 64kbit/s per call. The G.729 codec compresses the payload to 8kbit/s, giving you up to eight (8) times the capacity on the same connection. So you can cut bandwidth requirements without sacrificing call quality. Ideal for use in limited bandwidth scenarios (ADSL connections, international VoIP service, satellite connections, etc.). There are two most common G.729 codec extensions namely, G.729A and G.729AB. In G.729A, the generated frames contain 80 bits form the input frames of 10 milliseconds (10 ms) in duration. The input and output contain 16-bit pulse-code modulation (PCM) samples converted from or to 8-Kbps compressed data. The total algorithmic delay is 15 ms. In G.729AB, the parameters are the same as in G.729A plus reducing the effective signal bandwidth when there is no audio input known as voice activation detection (VAD). In order to avoid user distraction that can be caused by intervals of absolute silence, a technology known as comfort noise generation (CNG) produces a small amount of background pink noise during pauses in speech.