TESTER No. 137A

Tester No. 137A comprises receiving equipment with a capacitive probe only.  It is used for pair identification when tone is applied by apparatus in an exchange or by an oscillator forming part of a separate tester.

Includes the following apparatus:-
1 x Amplifier No. 109.
1 x Case No. 116A.
1 x Plug No. 420 with Cord 2/138AB.
1 x Probe No. 5.
1 x Receiver, Headgear No. 16.

Drawing - 91439.

Description - TI A2 A1001

Principle of operation - TI A2 A1003
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Last revised: December 05, 2025
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