SUBSCRIBER'S SIMPLE EXCHANGE

摘要

PURPOSE:To operate normally a loudspeaker telephone set and an exclusive terminal equipment by connecting a constant current circuit set to a constant current value in response to the telephone set connecting to an extension channel to each extension channel. CONSTITUTION:Constant current circuit 131... are connected to extension channels 31... and the operating current of a telephone set connecting to the extension channels 31... is obtained by the constant current circuit 131.... When a telephone set T connecting thereto requires a large power as a loudspeaker telephone set, the supply current of the relevant extension channel is increased by turning current setting switches SW1... for the constant current circuits 131... connecting to the relevant extension channels 31..., then the sound volume of the loudspeaker telephone set connected for the purpose is increased sufficiently and stable talking is attained.