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Typewriter Logic for Resolving Certain Ambiguities Arising During Repeat Chord Keying

IP.com Disclosure Number: IPCOM000052932D
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Churgovich, DM: AUTHOR [+3]

Abstract

With processor-controlled typewriters, outboard keybuttons are commonly used to invoke various operations (play, delete, etc.) involving text storage and certain keybuttons from the main keyboard may then be used concurrently (chord keying) to qualify the invoked operation for character-by-character, word-by-word or line-by-line operation. If a repeating keybutton, such as the backspace key or the space bar, is used to qualify an operation, for example, to be on a character-by-character basis, an opportunity arises for triggering an unwanted operation in the event the operator inadvertently releases the keys in the wrong order.

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Typewriter Logic for Resolving Certain Ambiguities Arising During Repeat Chord Keying

With processor-controlled typewriters, outboard keybuttons are commonly used to invoke various operations (play, delete, etc.) involving text storage and certain keybuttons from the main keyboard may then be used concurrently (chord keying) to qualify the invoked operation for character-by-character, word-by-word or line-by-line operation. If a repeating keybutton, such as the backspace key or the space bar, is used to qualify an operation, for example, to be on a character- by-character basis, an opportunity arises for triggering an unwanted operation in the event the operator inadvertently releases the keys in the wrong order.

This article describes logic that serves to ignore signals resulting from operator errors relating to the order in which keys are released after chord keying.

One approach for logic to ignore signals resulting from unintended continued depression of a repeat key during chord keying would be to wait a fixed time period after the outboard key is released before processing signals resulting from depression of the main keyboard key. A shortcoming of this approach, however, is that it is difficult to select a fixed time that is satisfactory for all operators.

A second approach takes into account the regularity of occurrence of signals from a depressed repeat key and detects a break in that regularity as an indication of a release of the key. Any subsequent ke...