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System for communicating digital data on a standard office telephone system

  • US 4,785,448 A
  • Filed: 02/25/1987
  • Issued: 11/15/1988
  • Est. Priority Date: 02/25/1987
  • Status: Expired due to Term
First Claim
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1. In combination with a local telephone network including a plurality of telephone handsets each located at a different station, and each adapted to be connected by a wire pair to a telephone exchange for communicating voice band signals therebetween, apparatus for enabling a plurality of digital data devices distributed amongst said stations to communicate data signals between one another over said wire pairs without interfering with said voice band signals, said apparatus comprising:

  • a plurality of station units, each located at a different one of said station, and each having a pair of station network terminals connected to a first end of one of said wire pairs;

    low pass filter means in each of said station units for coupling one of said telephone handsets to said pair of station network terminals;

    processing means in each of said station units responsive to data supplied by a data device connected thereto for outputting Manchester encoded data nd responsive to Manchester encoded data supplied thereto for outputting data to said data device;

    means including high pass filter means in each of said station units for coupling said processing means to said pair of network terminals;

    a plurality of hub units each having a pair of hub network terminals connected to a second end of one of said wire pairs;

    low pass filter means in each of said hub units for coupling said pair of hub network terminals to said telephone exchange;

    processing means in each of said hub units responsive to Manchester encoded data received at the hub network terminals of that hub unit for outputting related data to all other hub units for transmission via wire pairs to station units connected thereto; and

    means including high pass filter means in each of said hub units for coupling the processing means therein to the hub network terminals thereof.

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