Ringer circuit driver for private branch of exchange

Abstract

PURPOSE: To simplify the wiring or the like, to employ a power supply with a small capacity as a telephone set supplying power supply and to make exchange small by using a switching means so as to superimpose currents of a power supply for telephone set and a power supply for a ringer circuit drive with each other. CONSTITUTION: A voltage for driving a ringer circuit impressed to a telephone set 12 depends on a voltage for a power supply 21 for driving the ringer circuit and a voltage of a power supply 30 for feeding a telephone set and a current for driving the ringer circuit by the voltage for driving the ringer circuit flows to the ringer circuit of the telephone set 12 via telephone set lines L 1 , L 2 from a terminal connection section 14. A current whose direction varies repetitively with a ringer frequency flows to the ringer circuit of the telephone set 12, which is thereby driven. On the other hand, a negative terminal 30b of a power supply 30 for feeding the telephone set connects to a switch being a switching element 23 and is impressed to the telephone set via either of the telephone set lines L 1 , L 2 in response to the make/break state of the ringing signal. COPYRIGHT: (C)1992,JPO&Japio

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    Publication numberPublication dateAssigneeTitle
    US-6774559-B2August 10, 2004Matsushita Electric Industrial Co., Ltd.Metal vapor discharge lamp