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Pass-through modem supporting both analog and digital cellular data communications

  • US 5,878,078 A
  • Filed: 08/15/1996
  • Issued: 03/02/1999
  • Est. Priority Date: 08/15/1996
  • Status: Expired due to Term
First Claim
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1. A modem, comprising:

  • a serial data port for connecting to data terminal equipment communicating using digital data signals;

    a protocol processor, connected to the serial data port, for formatting and de-formatting the digital data signals;

    a data pump, connected to the protocol processor, for modulating the formatted digital data signals to output analog data signals, and also demodulating received analog data signals to output formatted digital data signals;

    a first analog data port, connected to the data pump, for connecting to an analog port of a cellular telephone network mobile station;

    a digital data port for making a digital data connection between the protocol processor and the cellular telephone network mobile station, the digital data connection carrying both said formatted digital data signals and call supervision signals; and

    the protocol processor further responding to received call supervision signals to control modem operation in a first mode to route formatted digital data signals between the mobile station and the data terminal equipment through the data pump, and also control modem operation in a second mode to route formatted digital data signals between the mobile station and the data terminal equipment through the digital data connection along with the call supervision signals by-passing the data pump.

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