PURPOSE: To attain quick and smooth accident preventing communication by calling a mobile receiver from a transducer or a main receiver in addition to the call of the main receiver by a transducer or a mobile receiver so as to apply communication.
CONSTITUTION: In hooking up a handset 4 of a main receiver 1, a hook switch 7 is switched, a voltage at a point (c) drops to invert the output of a comparator 16 to an L level, a transistor TR Q1 is turned on to apply power to a calling line l11, and buzzer 22 of mobile receivers 3a, 3b is energized to generate a call tone. In hooking up a handset 6 of the mobile receiver 3a in this state, the hook switch 9 is thrown to the position of the handset 6 and a voltage at a point (b) of the main receiver 1 reaches a reference voltage Vr1 or below and the output of the comparator 14 goes to an L level and the output of comparators 14, 16 goes to an L level, then the output of the comparator 24 is inverted to an L level, the TR Q3 is turned on to interrupt the TR Q1 to stop the call tone in other mobile receiver 3b.
SUZUKI MUNEMASA
MAKABE MASAYUKI
| JPS5632291B2 | 1981-07-27 | |||
| JP57188458B |
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