The battery ringing type of telephone is preferred by most railway companies for use in signal cabins, etc. The instruments illustrated have therefore been specially arranged for railway use and are simple, neat, efficient and durable for such service.
The instrument, microtelephone and terminal block cases are made of moulded
Bakelite and the interior apparatus, such as spring sets, battery bell or buzzer, condenser, induction coil and relay if required, are mounted on a base plate which is readily removable as a unit.
The N1104 type of instrument has a transmitter switch in the microtelephone handle, and two press buttons, one for ordinary ringing and the other for special selective ringing.
The telephone N1108 is also equipped with two press buttons, one to call the exchange and the other for code ringing, and the transmitter switch is operated by the replacement of the microtelephone on the cradle.
Overall dimensions 9.25 x 8 x 6 inches.
Weight 6.25 lb.
Telephone contains - 5000 ohm polarised relay, buzzer, condenser and 12-way terminal block.
Introduced around 1940.