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Military A.O.I.P, 1934.Their principal characteristics are beeing strongness and to be able to
work on any kind of network.
That's why they are compatible with local and common batteries.
Magneto and batteries are inside the case. They are easy to set up in
any conditions.
US Army, 1943.More than the ability to be connected on any network , they have a special function : one can use it as a spy (connected in parrallel on an existing line without beeing detected) . In this case, a push-to-talk button is used to transmit, like a semi-duplex radio. |
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Hotel switchboard, 1925.As soon as private installation increases, it becomes
necessary to use a switchboard. They are mainly used as small networks inside an hotel or a factory
7 lines switchboard CTTH, 1935.They are made of call sig. with metal plate (used also to memorize an incomming call) and switches to connect subscribers. Generally, subscriber's phones are not allowed to be connected directly on the network (see private phones). The switchboard is also an interface.
Western Electric. |
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 CTTH, 1925 |
This small switchboard has been manufactured during 30 years. The first version was based on
the PTT24 (same handset and induction coil), the latest is close to the U43.
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 CTTH, 1955. |
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8 chanels switchboard extensionIn big central phones, switchboards are generally
very important. An operator have to manage about 200 subscribers
with the same amount of jack plugs. When an operator does not have
enough room in front of him, some extensions are installed near the
primary switchboard.They are used to dispacth connections to an other
operator.
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| Copyright V. Lomba, Oct 98, may 2000 |
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