DIGITIZED VOICE MESSAGE STORAGE SYSTEM

The invention disclosed is a system for receiving, storing and retransmitting voice messages. The system includes a plurality of digital computers operating independently in parallel to supervise the system's operation. The system also includes a conversion subsystem to which a plurality of telephone lines may be connected. The subsystem converts between analog telephone signals and digital data which the system uses for message storage. The conversion subsystem includes a plurality of semi-autonomous sub-subsystems, one per telephone line connected to the system. Each sub-subsystem includes a microprocessor and a random access memory for storing the microprocessor's program and for temporarily storing the digitized voice data. The microprocessor monitors the status of the telephone line and controls the operation of the sub-subsystem's conversion of signals between analog telephone signals and the digital data stored within the system. The system also includes a mass storage subsystem in which digitized voice messages may be stored indefinitely. Multiple, semi-autonomous data transfer paths interconnect the mass storage subsystem and each sub-subsystem to which individual telephone lines are connected. The presence of these multiple, semi-autonomous data transfer paths over which the digitized voice messages are transmitted adapts the system for highly reliable operation. The reliable operation of the system is further enhanced by means of error detection of multiple simultaneous sub-subsystem selection. This selection error detecting means automatically and instantaneously terminates sub-subsystem selection if an error is detected.