Browse Prior Art Database

Bail Signal Bounce Eliminator

IP.com Disclosure Number: IPCOM000086709D
Original Publication Date: 1976-Oct-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Castle, WH: AUTHOR [+3]

Abstract

This invention eliminates extra keyboard signals which are caused by mechanical reed-switch actuator bounce and which are interpreted as new keyboard cycles by the logic.

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Bail Signal Bounce Eliminator

This invention eliminates extra keyboard signals which are caused by mechanical reed-switch actuator bounce and which are interpreted as new keyboard cycles by the logic.

A keyboard may actuate six reed switches, which may be wired as shown in the figure. The outputs of these switches are logic OR'ed to generate a keyboard strobe signal which tells electronic logic to sample the keyboard output. It is possible for one or more of the reed-switch actuators to bounce and cause the switches to open and close. This may result in more than one strobe signal, which causes a printer error.

This problem can be eliminated by installing an additional reed switch in the line between the common side of all the switches and signal ground. This switch would be closed for the short period of the keyboard cycle when valid bail-code output is possible, and open the rest of the time. This will effectively stop the generation of false strobe signals because, even if any of the six reed switch actuators bounce, the new switch will be open to prevent the bail outputs from changing.

It is imperative that the actuator for this switch not bounce. The required action can be obtained by positively driving the actuator.

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