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Automotive electronic communication apparatus with theft disabling, particularly car radio or similar automotive audio equipment

  • US 4,808,981 A
  • Filed: 03/29/1988
  • Issued: 02/28/1989
  • Est. Priority Date: 05/21/1987
  • Status: Expired due to Fees
First Claim
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1. Automotive electronic communication apparatus with theft disabling, particularly car radios or similar automotive audio equipment, comprisinga memory (5) for storing(a) a selected code word, and(b) an impedance value;

  • input means (1,

         4) for entering code words into the memory;

    means (1) for preventing operation of the communication apparatus (2) until the selected code word is entered for storage into the memory after removal of the radio,and comprisingmeasuring means (7, 7'"'"') coupled to an accessory terminal (9) of the communication apparatus (2) and measuring impedance of accessory equipment (8) connected to said terminal; and

    comparator means (1) coupled to the communication apparatus (2) and controlling operation thereof, said comparator means comparing the impedance of the accessory equipment (8) coupled to said accessory terminal (9) with the impedance value stored in the memory (5) and(i) upon coincidence, permitting operation of the communication apparatus (2), and(ii) upon non-coincidence, inhibiting operation of the communication apparatusuntil the selected code word, stored in the memory, is again entered into the input means (1,

         4).

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