TELEPHONE No. 311
Introduced in 1950, this Bakelite cased, combined handset wall telephone (equivalent to the table Telephone No. 310) was used by the BPO in auto areas on shared service with selective ringing and metering.
The telephone had a single press button situated above the dial.
Mark 1 & Mark 2 - do not exist.
The phone case is released from the back plate by one screw
on the right hand side of the case. The whole body,
complete with chassis, swings open to the left, away from the
back-plate which is fixed to the wall.
This phone was superseded by the Telephone No. 321 which was fitted with a Thermistor (this reduced the number of components and thus the cost of the phone).
Supplied to the BPO by British Ericsson, their model No. N1071D.
Diagram for telephone circuit - N411.
Diagram for Button labels - N620.
Last revised: June 06, 2020