Multiplexing system line fault isolation and identification
First Claim
1. A multiplexing system for two-way data transmission over a single transmission line between a control station and a plurality of remote transponder units, the control station including transmitter-receiver means for selectively addressing the transponder units and receiving response signals therefrom, wherein the transmission line is configured as a loop terminating at each end at the control station, the transmitter-receiving means being coupled to respective ends of the transmission line for transmitting address signals to the transponder units and receiving response signals therefrom, the transmission line thereby furnishing two communication paths between the control station and each transponder unit, said transmitter-receiver means including means for differentiating between response signals received via the two ends of the line, and the transponder units being distributed along the transmission line and connected thereto by respective line connection circuits each comprising:
- a two-state impedance device having high and low impedance states, the devices of the respective units being serially interconnected in said line,respective output means connected to the line on opposite sides of the impedance device for transmitting said response signals via the two communication paths,respective input means connected to the line on opposite sides of the impedance device for receiving address signals transmitted via the two communication paths, andlogic circuit means coupled to said input means and operable in response to address signals received by both input means to switch said impedance device from a high to a low impedance state.
1 Assignment
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Accused Products
Abstract
In a multiplex signalling system for two-way data transmission over a single transmission line, the line is configured as a loop terminating at each end at a central or control station, thereby furnishing two communication paths between the central station and each of a plurality of remote stations distributed along the line. Transmission of signals from the central station and reception of signals at the control station are duplicated at the line ends so that an open line fault can readily be identified from an analysis of signals received at the central station. Switches at the remote stations operable in accordance with reception of signals along both communication paths serve to isolate and identify line ground faults.
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Citations
4 Claims
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1. A multiplexing system for two-way data transmission over a single transmission line between a control station and a plurality of remote transponder units, the control station including transmitter-receiver means for selectively addressing the transponder units and receiving response signals therefrom, wherein the transmission line is configured as a loop terminating at each end at the control station, the transmitter-receiving means being coupled to respective ends of the transmission line for transmitting address signals to the transponder units and receiving response signals therefrom, the transmission line thereby furnishing two communication paths between the control station and each transponder unit, said transmitter-receiver means including means for differentiating between response signals received via the two ends of the line, and the transponder units being distributed along the transmission line and connected thereto by respective line connection circuits each comprising:
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a two-state impedance device having high and low impedance states, the devices of the respective units being serially interconnected in said line, respective output means connected to the line on opposite sides of the impedance device for transmitting said response signals via the two communication paths, respective input means connected to the line on opposite sides of the impedance device for receiving address signals transmitted via the two communication paths, and logic circuit means coupled to said input means and operable in response to address signals received by both input means to switch said impedance device from a high to a low impedance state. - View Dependent Claims (2, 3, 4)
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Specification