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Data processing system having a programmable modem and method therefor

  • US 6,408,059 B1
  • Filed: 11/08/1999
  • Issued: 06/18/2002
  • Est. Priority Date: 10/16/1997
  • Status: Expired due to Fees
First Claim
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1. A system comprising:

  • a modem microprocessor responsive to predetermined signals to access a country code table, extracting information relating to the predetermined signals and using said information to generate configuration signals representative of a country telecommunication standard;

    a ring detect circuit operatively coupled to said microprocessor, said ring detect circuit including a first digital-to-analog converter, responsive to the configuration signal, operatively coupled to the microprocessor;

    a second digital-to-analog converter, responsive to the configuration signal, operatively coupled to the microprocessor;

    a first rectifying circuit;

    a capacitor operatively coupling the rectifying circuit to a first terminal;

    a conductor operatively coupling the rectifying circuit to a second terminal;

    a variable resistor operatively coupled to the rectifying circuit and the first digital-to-analog converter;

    a variable voltage source operatively coupled to the rectifying circuit and the second digital-to-analog converter;

    an operational amplifier connected to the rectifying circuit, the variable resistor and the variable voltage source; and

    a feedback loop interconnecting the operational amplifier to the modem microprocessor.

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