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Automatic Telephone Dialer

IP.com Disclosure Number: IPCOM000077009D
Original Publication Date: 1972-May-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Palmer, RS: AUTHOR

Abstract

This low-cost logic implementation for automatic telephone dialing features field programmable numbers, variable-digit length compatibility and a unique shift register for both memory and timing functions. The automatic dialer shown in Fig. 1 consists of a serial-in/parallel-out digit shift register 1, programmable pins to set in the phone number 2, a parallel-in and serial-out dialing/timing register 3, a telephone relay 4, control logic 5 and a clock 6.

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Automatic Telephone Dialer

This low-cost logic implementation for automatic telephone dialing features field programmable numbers, variable-digit length compatibility and a unique shift register for both memory and timing functions. The automatic dialer shown in Fig. 1 consists of a serial-in/parallel-out digit shift register 1, programmable pins to set in the phone number 2, a parallel-in and serial-out dialing/timing register 3, a telephone relay 4, control logic 5 and a clock 6.

The control logic is shown symbolically with a "cube" form in Fig. 2. The digit register is initially loaded for the most significant digit and the dialing shift register is loaded according to the number programmed in the pins. Next, the dial register is successively tested for overflow, then shifted until dial overflow occurs. Each shift cycle represents a make/break telephone connection through the relay. Once overflow occurs, latch 7 inhibits the relay but shift cycles continue equal to the time required between dialing of two digits. Timing register overflow indicates this dwell time and the relay inhibit latch 7 is reset. Then, the control logic shifts the digit register one position, whereupon the sequence repeats. When overflow of the digit register occurs, the unit's operation is complete and the control returns to the reset state. The clock controls the dialing frequency so as to be compatible with central telephone equipment.

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