|MINE TELEPHONES AND SIGNALLING APPARATUS
Wall Pattern - with Hand Micro-telephone
Polished wood case with hinged front, making for maximum accessibility. Front secured by two captive screws. High resistance; screened ringer with special gong adjustment; detachable
switch-hook. Hand micro-telephone with convenient curved grip, supporting capsule-type microphone and hygienic mouthpiece. Two-pole receiver, 65 ohms resistance.
The generator has a double cut-out, and is wound to 500 ohms. An induction coil and internal terminals for connecting the lines and battery complete the equipment.
Height, 9.5ins. width, 6.75ins. depth, 5.75ins.
Weight, 11 lbs.
Wall Pattern - with Separate Transmitter and
Similar specification to T.1122 above, but fitted with capsule microphone, mounted on front of case, and separate two-pole receiver
of 65 ohms resistance.
Dimensions and weight as T.1122.
Taken from the ATM Mine Telephones and Signalling Apparatus Catalogue 1928