PURPOSE: To facilitate an easy construction for installation of a telephone device by converting the circuits needed for a main device into ICs or semiconductors and storing them into a master telephone.
CONSTITUTION: A circuit of the main wire led from a central office is stored to line terminals L1 and L2 of a master telephone set STa. Then a diode bridge DB, a pulse transmission circuit PS and a talking circuit TKa are connected to the main wire via dividing switches LK1 and LK2, relay contacts la1 and la2 and hook switches HAa1 and HSa2. At the same time, two slave telephone sets are connected to the main wire via relay contacts lb1 and lb2 and a talking line Lt. A control circuit CNT within the STa transfers the data signals with a transmission/reception circuit of each slave telephone via a speech transmission/ reception circuit SRa and a signal line Ls. Then the CNT receives the operation information of a push-button switch CKb for extension call and also controls the glowing condition of a main wire pilot lamp LLb to control whether the output of a toner generator TG is transmitted with superposition to the line Ls.
NASHIKI NOBORU
OOTA TAKEO
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