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These are switches that were inherited by the GPO when they took over the
National Telephone Company.
| Switch, N.T. No. 3 A 2 way metallic
switch.
Superseded by Switch, 6-terminal, 2-Position.
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| Switch, N.T. No. 5 An Intermediate
through switch of 8 terminals and 3 positions.
Includes:-
Label No. 128, engraved "Exchange -Through - Private".
Used with a Bell No. 1A
Superseded by the Switch, N.T. No. 14.
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| Switch, N.T. No. 6 Intermediate,
private, 8-terminal, 2-position, switch.
Includes:-
1 x Label No , engraved "Intermediate, Private".
Requisitions should give details if other engraving is
required.
Used with a Bell No. 1A.
Superseded by the Switch, N.T. No. 15.
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| Switch, N.T. No. 14 3 position switch
used on Extension Plans No. 5, 5A, 7 & 7A. These are
used when there is a main phone and an extension phone, when
intercommunication is required between the main and extension
telephones.
Intermediate, through, 7-terminal, 3-position, switch.
The picture shows a later switch with a round knob whilst
earlier switches used a handle. The Label is engraved "Exch -
Through - Extn".
Includes:-
1 x
Magneto bell 1,000ohms.
1 x
Indicator. Supersedes Switch N.T. No. 5 with Bell No. 1A. It was still in the GPO
Rate Book in 1933.
Diagram - N.T. 10565.
Click on picture to enlarge.
Click for early model
with handle switch
Click
for later model with turn knob switch
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| Switch, N.T. No. 15 Intermediate,
private, 7-terminal, 2-position, switch.
Includes:-
Magneto bell 1,000ohms.
Indicator.
Supersedes Switch, N.T. No. 6 with Bell No. 1A.
Diagram - N.T. 10564.
Click on picture to enlarge
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| Switch, N.T. No. 17 Electro-magnetic,
100ohm switch.
For use with Repeaters, Telephonic on cord circuits.
Dimensions overall 10.5" x 3.25" x 3".
No superseding item.
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| Switch, N.T. No. 19 Comprises of one Key
No. 62 and signal (11ohms), mounted in woodwn case. For C.B.
extension working.
Superseded by arrangement shewn in Diagram C.B. 8.
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| Switch, N.T. No. 20 For 2 C.B. Exchange
lines with single extension with secrecy against main and no
intercommunication.
This switch was used
on the Extension Plan No. 8A and was still in the GPO portfolio
in 1933.
The switch was superseded by the Switch, Indicator and Key N601
around 1938. Includes:-
2 Indicators, grid type, 15w with 50w non-inductive shunt.
1 Key No. 101. Diagram - C.B. 1163. |
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