T268 - T273

Type Certified by The Mines Department, Certificate No. T/Tel/25, as intrinsically safe.

Ironclad Cordless Telephone Switchboards robustly constructed for use underground in conjunction with magneto mine telephones of the certified type. Strong cast-iron case fitted with hinged lid on which are mounted the various working components, keys, etc., making for accessibility.

Connections are made by means of keys, and there are no cords or flexible connections to wear or break. Conversations can be continued whilst the board is under examination. The indicator drop shutters are fitted with contacts for ringing extension bells and are mechanically reset by an external knob.

These switchboards can be supplied with any number of ways and fitted with one, two or four through positions, enabling a corresponding number of conversations to take place simultaneously.

Model number and capacity
T.268 3 lines 1 through position fitted. L10in, W9.8in, D7in.
T.269 4 lines 2 through positions fitted. L13in, W9.8in, D7in.
T.267 6 lines 2 through positions fitted. L15.5in, W10in, D7in.
T.270 10 lines 4 through positions fitted. L21.5in, W15.8in, D7in.
T.271 12 lines 4 through positions fitted. L24in, W15.8in, D7in.
T.272 20 lines 4 through positions fitted. L30.5in, W22in, D7in.
T.273 30 lines 4 through positions fitted. L30.5in, W33.3in, D7in.

Taken from the A.T.M. Mine Telephones and Signalling Equipment Book - April 1939

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Last revised: October 06, 2012