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Having Secrecy
In Pararel Telephones |
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Often a need
arises for connection of two telephone instruments in parallel to
one line. But it creates quite a few problems in their proper
performance, such as overloading and overhearing of the
conversation by an undesired person. In order to eliminate all
such problems and get a clear reception, a simple scheme is
presented here (Fig. 1).
This system will enable the incoming ring to be heard at both the
ends. The DPDT switch, installed with each of the parallel
telephones, connects you to the line in one position of the switch
and disconnects you in the other position of the switch. At any
one time, only one telephone is connected to the line. To receive
a call at an end where the instrument is not connected to the
line, you just have to flip the toggle switch at your end to
receive the call, and act as usual to have a conversation. As soon
as the position of the toggle switch is changed, the line gets
transferred to the other telephone instrument.
Mount one DPDT toggle switch, one telephone ringer, and one
telephone terminal box on two wooden electrical switchboards, as
shown in Fig. 3. Interconnect the boards using a 4-pair telephone
cable as per Fig. 1. The system is ready to use. Ensure that the
two lower leads of switch S2 are connected to switch S1 after
reversal, as shown in the figure.
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Click
Here For Circuit Diagram
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