This Telecommunication Standard (TS) describes the detailed mapping from input blocks of 320 speech samples in 16-bit uniform PCM format to encoded blocks of 132@ 177@ 253@ 285@ 317@ 365@ 397@ 461 and 477 bits and from encoded blocks of 132@ 177@ 253@ 285@ 317@ 365@ 397@ 461 and 477 bits to output blocks of 320 reconstructed speech samples. The sampling rate is 16 000 samples/s leading to a bit rate for the encoded bit stream of 6.60@ 8.85@ 12.65@ 14.25@ 15.85@ 18.25@ 19.85@ 23.05 or 23.85 kbit/s. The coding scheme for the multi-rate coding modes is the so-called Algebraic Code Excited Linear Prediction Coder@ hereafter referred to as ACELP. The multi-rate wideband ACELP coder is referred to as MRWB-ACELP.