03967273 is referenced by 136 patents and cites 6 patents.

The disclosure comprises a method and apparatus for using a pushbutton telephone keyboard in which a signal sequence representing a unique symbol is generated by pushing a first button on which the desired symbol is located, each button being labeled with at most a three by three array of symbols, and pushing a second button, which is indicated by the position of the symbol in the array on the first button. Letters and numbers are arranged corresponding to the arrangement of a standard typewriter keyboard, insuring that anyone familiar with the location of letters and numbers on a typewriter can quickly find the letter on the keyboard.

Title
Method and apparatus for using pushbutton telephone keys for generation of alpha-numeric information
Application Number
5/456029
Publication Number
3967273
Application Date
March 29, 1974
Publication Date
June 29, 1976
Inventor
Kenneth Charles Knowlton
Plainfield
NJ, US
Agent
R O Nimtz
Assignee
Bell Telephone Laboratories Incorporated
NJ, US
IPC
H04L 15/04
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