The DS2165 ADPCM processor chip is a dedicated digital-signal-processing (DSP) chip that has been optimized to perform adaptive differential pulse-code modulation (ADPCM) speech compression at three different rates. The chip can be programmed to compress (expand) 64kbps voice data down to (up from) either 32kbps, 24kbps, or 16kbps. The compression to 32kbps follows the algorithm specified by CCITT recommendation G.721 (July 1986) and ANSI document T1.301 (April 1987). The compression to 24kbps follows ANSI document T1.303. The compression to 16kbps follows a proprietary algorithm developed by Dallas Semiconductor. The DS2165 can switch compression algorithms on-the-fly. This allows the user to make maximum use of the available bandwidth on a dynamic basis.