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. |
