TELEPHONE No. 311


Introduced in 1948, this Bakelite cased, combined handset wall telephone (equivalent to the table Telephone No. 310) was used by the BPO in automatic areas on shared service lines with selective ringing and metering. 

The telephone had a single press button situated above the dial.

The phone has an integral relay, that stopped bell tinkle and two rectifier units.  These components are also fitted in a Bellset No. 41A, which was always installed with the table model, the Telephone No. 310.

Produced in Black, Chinese Red, Ivory and Jade Green.

Mark 1 & Mark 2 - do not exist.
Mark 2A - has a Receiver, Inset No. 2P in the handset and switch bracket/ plungers of an improved design.

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.  The back plate on this telephone has pressed standoffs for the wall mounting.

This phone was superseded by the Telephone No. 321 .  The Telephone No. 321 was fitted with a Thermistor (which replaced the relay and rectifier packs).  This is a very small component compared to the relay and rectifiers, which greatly reduced the cost of the phone.

Superseded by Telephone No. 711 in 1964.

Supplied to the BPO by British Ericsson, their models:-
Telephone No. 311F - No. N1071D1.
Telephone No. 311L - No. N1071D2.

Diagram for telephone circuit - N411.

Diagram for Button labels - N620.

Drawing - 90116.

Keys for use in 300 type Wall and Table Telephones

History, Technical and General Information on 300 type telephones

Development of the Bakelite Wall Telephone

How to wire your Telephone No. 311 to make it work on Plug and Socket

Collectors information

Comparison chart of GPO 300 type telephones

Click here for an article from the Ericsson Bulletin


 

The chassis when installed in the case
 
Chassis removed - showing the rectifiers and additional capacitor
 
Another view of the chassis showing the relay underneath the capacitor
 
Telephone Paster diagram

 

 

 
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Last revised: May 24, 2021

FM