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    Circuit for automatically releasing holding state of telephone system
    2.
    发明授权
    Circuit for automatically releasing holding state of telephone system 失效
    电路自动释放电话系统的保持状态

    公开(公告)号：US4551582A

    公开(公告)日：1985-11-05

    申请号：US595387

    申请日：1984-03-30

    申请人： Nobuo Matsuo

    发明人： Nobuo Matsuo

    IPC分类号： H04Q3/58 ,  H04M1/72 ,  H04M1/80 ,  H04M3/428 ,  H04M1/00

    CPC分类号： H04M3/4283 ,  H04M1/80

    摘要： An automatic telephone hold releasing circuit for a plurality of telephone sets connected in parallel across a pair of wires of a subscriber's office line, which can automatically release a call placed on hold at one of the telephone sets even when the particular telephone set is on hold with its handset placed in the on-hook position. The circuit comprises means for detecting a voltage drop occurring in the voice-circuit when the handset of a telephone set other than that with which the call has been initially answered is unhooked, means for comparing the dropped voltage with a voltage present when the call was put on hold, and means responsive to an output of said comparing means for deenergizing a relay to open its contacts in response to the voltage drop and automatically release the initially answered telephone set.

    摘要翻译： 一种用于多个电话机的自动电话保持释放电路，用于并联连接在用户办公室线路的一对电线上，即使当特定电话机处于保持状态时，它也可以自动地释放在其中一个电话机上保持的呼叫 其手机放置在挂机位置。 所述电路包括用于当所述电话机以外的所述电话机的所述手机未被初次接听时，检测所述语音电路中发生的电压降的装置，用于将所述下降的电压与所述呼叫存在的电压进行比较的装置 并且响应于所述比较装置的输出响应于电压下降并自动释放最初应答的电话机，对继电器断电以打开其触点的装置。