G.726 is an ITU-TADPCM speech codec standard covering the transmission of voice at rates of 16, 24, 32, and 40 kbps. It was introduced to supersede both G.721, which covered ADPCM at 32 kbps, and G.723, which described ADPCM for 24 and 40 kbps. G.726 also introduced a new 16 kbps rate. The four bit rates associated with G.726 are often referred to by the bit size of a sample, which are 2-bits, 3-bits, 4-bits, and 5-bits respectively.
The most commonly used mode is 32 kbps, since this is half the rate of G.711, thus increasing the usable network capacity by 100%. It is primarily used on international trunks in the phone network. It also is the standard codec used in DECT wireless phone systems and is used on some Canon cameras.