公开(公告)号：US4825196A

公开(公告)日：1989-04-25

申请号：US141662

申请日：1987-12-04

申请人： Toshikazu Morita

发明人： Toshikazu Morita

IPC分类号： A62C37/00 ,  A62C2/24 ,  G08B17/00 ,  G08B25/04 ,  G08B1/00 ,  H04Q1/30

CPC分类号： G08B25/04

摘要： A signal transmission circuit provided with a control panel or a terminal device of a fire/security protection system is arranged so as to transmit a signal for the control panel or terminal device to a signal line. The signal transmission circuit includes: a signal transmission which is enabled when transmitting a signal under the control of a signal processing portion; a signal detector for detecting the signal transmitted from the signal transmitter to the signal line; a timer which is set when the signal is transmitted and is reset by the detection output from the signal detector, and a signal transmission controller for turning off the signal transmitter when the time count output of the timer exists during a predetermined time interval.