G.726 is ITU-T speech codec operating at bit rates of 16-40 kbit/s. The most commonly used mode is 32 kbit/s, since this is half the rate of G.711, thus increasing the usable network capacity by 100%. G.726 is based on ADPCM technology. ITU standardized G.726 for the first time in 1984. Several additions to the standard have been done later. The additions include additional modes (originally G.726 was only 32 kbit/s), elimination of all-zero codewords. The ITU Telecommunication Standardization Sector (ITU-T) coordinates standards for telecommunications on behalf of the International Telecommunication Union (ITU) and is based in Geneva, Switzerland. ... Speech coding is the compression of speech (into a code) for transmission with speech codecs that use audio signal processing and speech processing techniques. ... Jump to: navigation, search G.711 is an ITU-T standard for audio companding. ... Pulse-code modulation (PCM) is a modulation technique. ...

G.727 includes the same bit rates as G.726, but is optimized for PCME Packet Circuit Multiplex Equipment environment. This is achieved by embedding 2-bit quantizer to 3-bit quantizer and same for the higher modes. This allows dropping of the least significant bit from the bit stream without adverse effects on speech signal.

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