Tandem Computers Incorporated

Carl W Kagy

David Allen Brown

William P Bunton

William J Watson

David P Sonnier

David B Brown

Stephen R Bissell

David L Aldridge

Daniel D Gunn

David P Sonner

A digital control circuit is constructed to use a single signal line for the dual functions of control and sensing the presence of the controlled device. The control circuit includes a driver element having an output capable of being placed in a high impedance allowing the signal line to be pulled to a first predetermined voltage potential when the controlled device is connected thereto, and a second voltage potential when the controlled device is absent therefrom. A receiver circuit monitors the signal line to sense presence of the one or the other of the voltage potentials.

Apparatus for unit control and presence detection

A power switching circuit module includes two power rails coupling independent power supplies to the input of a DC controller and test circuits to detect latent faults in power mixing devices included in the circuit.

System for switching power and scrubbing power mixing devices for faults

Growing community of inventors

Cedar Park, TX, United States of America

Carl W Kagy