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Voice/data digital, duplex link

  • US 4,549,290 A
  • Filed: 06/10/1983
  • Issued: 10/22/1985
  • Est. Priority Date: 06/10/1983
  • Status: Expired due to Term
First Claim
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1. Link apparatus connected to one end of a pair of communication lines for simultaneously sending and receiving digital data over the lines, the link apparatus comprising:

  • a transmitting circuit for generating digital signal pulses and for transmitting them over the pair of communication lines and including means for detecting each change of state of said digital signal pulses and for generating a control signal pulse at each such change of state,a receiving circuit for receiving data signals generated by an external source and transmitted over the communication lines to the link apparatus, the receiving circuit comprising means for discriminating between data signals received over the communication lines and the digital signal pulses generated by the transmitting circuit and for outputting said data signals, controllable switch means supplied with the control signal pulse for interrupting the outputting of said data signals by the discriminating means in response to the control pulse, and storage means for storing the value of the last received data signal from the external source prior to the interruption by the switch means, and wherein the switch means is connected in series between the discriminating means and the storage means.

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