The PCM codec is designed to perform transmit encoding analog/digital (A/D) conversion, receive decoding digital/analog (D/A) conversion, and transmit and receive filtering for voice-band communications systems. The device operates in either the 15-bit linear or 8-bit companded (u-law or A-Law) mode, which is selectable through the I2C interface. The PCM codec generates its own internal clocks from a 2.048-MHz master clock input.