GSM 06.10 specifies the detailed mapping between input blocks of 160 speech samples in 13 bit uniform PCM format to encoded blocks of 260 bits and from encoded blocks of 260 bits to output blocks of 160 reconstructed speech samples. The sampling rate is 8000 samples/s leading to an average bit rate for the encoded bit stream of 13 kbit/s. The encoding scheme is the so-called Regular Pulse Excitation Long Term prediction Linear Predictive Coder, here-after referred as RPE-LTP. The document also specifies the conversion between A- and u-law (PCS 1900) PCM and 13 bit uniform PCM. The second document specifies the speech codec to be used for the GSM half rate channel.