Successive key operating mechanism for telephone dialing

Claim 1

An input device for key telephone sets comprising: an input means having ordinary numeral and alphanumeric push button keys as that provided in a key telephone set for inputting telephone call information therewith, and including a plurality of control means functionally disposed in conjunction with the numeral and alphanumeric push button keys for being operated to effect "circulatory" input operations in alphanumeric and numeral modes; a plurality of display means functionally disposed in said input means in conjunction with the push button keys and said control means for displaying input mode and keyed information thereon; circuit means electrically coupled with said input means and said display means in connection with each of the numeral and alphanumeric push button keys and said control means for processing keyed information by comparing and counting operations so as to effect input mode setting and changing functions on a "circulatory" basis; so that a telephone call can be conveniently made either through numerals or alphabetical letters or through the combination of both, said circuit means comprising a first counter matched with a decoder electrically connected to the push button keys for providing an output enable to each one of the push button keys; a pair of latches coupled with the push button keys and said control means for temporarily latching keyed input data information therein and outputting the same therefrom; a frequency generating means electrically connected to said first counter through an AND gate for providing keying scanning signals therefrom; a memory means coupled with said ALPHA key through a flip-flop circuit arrangement for storing keyed input data information and providing a key code therefrom; a comparator means electrically connected between said latches and said memory means for comparing input data information from said latches and outputting compared keying information therefrom; a second counter electrically connected to said comparator means, said control means and said memory means for providing keyed input information in effecting input mode setting and changing operations in accordance with said compared keying information from said comparator means; and a position counter means coupled with said second counter and said control means for providing said display means with display position count information in conjunction with said comparator means.