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Security device utilizing conventional telephone lines

  • US 4,493,947 A
  • Filed: 10/06/1981
  • Issued: 01/15/1985
  • Est. Priority Date: 10/06/1981
  • Status: Expired due to Fees
First Claim
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1. A security device connected to telephone lines and to at least one sensor, comprising:

  • monitoring means for monitoring said at least one sensor to determine a status of each said at least one sensor and to detect when said status of any sensor is a fault status;

    preselecting means operable by a user of the security device for preselecting at least one telephone number to be called upon occurrence of said fault status;

    automatic call-up means for automatically calling said preselected telephone number to report any said fault status;

    answering circuit means for receiving and answering an incoming telephone call received over said telephone lines, and responsive to reception of a user input transmitted over the telephone lines and designating a selected said at least one sensor to be monitored for monitoring said at least one sensor, and for transmitting the status of said selected at least one sensor over the telephone lines; and

    identification circuit means responsive to a received user query, requesting the identity of the security device, for transmitting identification information over the telephone line;

    wherin said identification circuit means comprises a counter for counting through a plurality of count outputs, a digital switch having multiple stages, each preset with a digit of an identifier, and a tone generator for selectively generating a pluraliyt of tones, said multiple stages of said digital switch being responsive in turn to respective count outputs for sequentially activating said tone generator to generate corresponding sequential tones, whereby to transmit said identification information.

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