Digital telephone answering machine with software and speech memories

摘要

The digital signal processor (DSP) has an internal read-only memory (ROM) for software and is connected to a speech memory (MEM) which may be a commercial audio random-access memory or an electrically erasable programmable read-only memory. An analogue interface connects the processor to a microphone (M) and loudspeaker (L). A PCM code can be connected through a digital interface (I/O) independent of the computer interface (HOST) which permits command, status, message and parameter transfers to and from a microcontroller (MC).