A single-chip controller for digital answering machines

A single-chip controller for digital answering machines is introduced. Only two other devices, an audio quality DRAM (ARAM) and a codec, are needed to implement all the digital parts of such an answering machine. The device performs voice compression and decompression algorithms, dual-tone multifrequency (DTMF) detection, voice synthesis, and control functions of digital answering machines.<
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