Mining Wall Telephone
N 1150 (shown)
Suitable for use in mines, ships, engine rooms, railway yards or any exposed positions.
Enamelled cast iron case with wide rnachined flange joint between body and front to render the instrument flame-proof, the joint being suitably packed to make it watertight.
The receiver, fitted within the case, is of the "loud speaker" type, having a flexible metallic listening tube with earpiece.
The transmitter is of the interchangeable "inset" type protected by moisture-proof shield and metal grid.
The induction coil, switch and connecting terminals are mounted on ebonite.
The switch, which is very substantially designed, has three positions:- "normal", "ring", and "speak".
The screws in the connecting terminals are specially large and very accessible.
All coils are treated to prevent the detrimental and corrosive effects of moisture and gases, etc., and the internal connections are made with special, heavily-insulated stout wire.
The instrument is designed for use with separate bell, or relay and bell, also external speaking and ringing battery, for which see "Accessories and Parts Section".
Overall dimensions 9 x 9 x 6 inches
Taken from the Ericsson catalogue, edition 26
Both introduced around 1931/1932.
The model N1149 is similar, but uncertified instruments having a capacitor in the speech path and if required a relay for long line working mounted under a metal cover on top of the telephone, can be supplied.
These telephones are not to be used in areas of risk.
Taken from the Ericsson catalogue, edition No. 60
Last revised: October 02, 2019