Instruction announcing system for modified telephone number dialling - uses PROM and RAM controlling voice synthesiser to inform dialler of disconnected or modified number when triggered

Abstract

Abstract The system allows a caller, who has dialled a disconnected or modified number, to be given appropriate instructions from a RAM and voice synthesiser circuit. A PROM is used to store typically used words and numerals from zero to nine. A programmer selects the required words from the PROM, by use of a keyboard, to transfer them into the RAM. There is provided a voltage detection circuit which triggers the instruction message arrangement. In use, each PROM contains 8 messages which each last for 5 seconds, and ten numbers, requiring 100K. The data exchange operations are controlled by a microprocessor. The entire circuitry is lodged in a small housing and is plugged into a subscriber line.

Inventors

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