Fire Patents (Class 379/43)
  • Patent number: 4656652
    Abstract: An emergency warning device comprises an alarm signal circuitry incorporated in the telephone lines of various telephone systems such as an existing party-line telephone system, or interphone system and it is adapted to issue an alarm call in case of emergency. The control circuitry provides a warning message of a state of emergency affairs that can be given to a user by a party-line telephone or the like in case of emergency.
    Type: Grant
    Filed: December 13, 1984
    Date of Patent: April 7, 1987
    Inventor: Kyoichi Nagai