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公开(公告)号：US3971898A
公开(公告)日：1976-07-27
申请号：US558476
申请日：1975-03-14
CPC分类号： H04M9/003
摘要： A visual indicator control circuit for use in key telephone systems is disclosed. The circuit includes a plurality of light emitting diodes connected in series and operated by a plurality of transistors having collector-emitter paths connected in parallel with the light emitting diodes. Circuits are provided for controlling the respective base electrode voltages of the transistors corresponding to the use status of each line to control the light emitting diodes corresponding to the on or off states of the transistors.
摘要翻译： 公开了一种用于关键电话系统的视觉指示器控制电路。 电路包括串联连接并由多个具有与发光二极管并联连接的集电极 - 发射极路径的晶体管操作的多个发光二极管。 提供电路用于控制对应于每条线的使用状态的晶体管的各个基极电压，以控制对应于晶体管的导通或截止状态的发光二极管。
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公开(公告)号：US4024353A
公开(公告)日：1977-05-17
申请号：US623488
申请日：1975-10-17
申请人： Tokuhisa Hijikata
发明人： Tokuhisa Hijikata
CPC分类号： H04M9/006
摘要： A line circuit for a key telephone system is provided with a first relay normally energized and a second relay for speech supervision. The operation of the first relay establishes a circuit for holding the second relay and the first relay is released by the voltage drop of a control line normally connected to a line holding control circuit and a visual indication circuit, respectively, at the manual operation of a non-lock type hold key to establish an intermittent signal for line holding indication. A switching transistor is provided in a circuit including the first relay so that the first relay is not energized by the signal intermitently sent to the visual indication circuit, so as to control the line hold control circuit and the visual indication circuit by one control line.
摘要翻译： 用于密钥电话系统的线路电路具有正常通电的第一继电器和用于语音监视的第二继电器。 第一继电器的操作建立一个用于保持第二继电器的电路，并且通过在通常连接到线路保持控制电路和可视指示电路的控制线路的电压降下分别释放第一继电器 非锁定型保持键建立线路保持指示的间歇信号。 开关晶体管设置在包括第一继电器的电路中，使得第一继电器不被间断发送到视觉指示电路的信号通电，从而通过一个控制线控制线路保持控制电路和可视指示电路。
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