TELEPHONE No. 11


OLD STYLE NEW STYLE (Mark 238) NEW STYLE


Standard Local Battery wall telephone - similar to Telephone No. 3 but with the addition of a generator.  Used on Magneto or C.B.S. circuits.

Wooden cased with generator and sloping writing shelf.

There are also numerous differences between the early and new models.  The later variant has a less ornate casing (cheaper to produce) and different Gravity switch and Generator.  The Gravity switch is a new design where the contact springs are operated by an Ebonite rod.  This ensures that the receiver hook is insulated from the line, in case of a high voltage contact between external overhead cables.

Fitted with Transmitter No. 6 on early types, then Transmitter No. 2 and finally Transmitter No. 22 on later variants.

Mark 238 Telephone includes (1928):-
1 x Bell No. 1A, unmounted. (Earlier types had Bell No. 9A).
1 x Coil, Induction No. 1, or No. 12.
4 x Cord, Instrument No. 116.
1 x Cord, Instrument No. 222.
1 x Frame, Notice No. 1. (Earlier types had Frame, Notice, No. 2, and Labels No. 530).
1 x Generator No. 40 (Earlier types had Generator No. 2A).
1 x Glass No. 3.
1 x Hook, Receiver F.
1 x Receiver, Bell No. 1A.
1 x Transmitter No. 2. (Earlier type had Transmitter No. 6).
4 x Fixing screws.

Frames, Notice, No. 2, and Labels No. 53C, will not be maintained in the old type of these instruments.

Telephone included (1946):-
1 x Bell No. 1A, Unmounted.
1 x Frame, Notice No. 1 (No. 9A for earlier supplies).
1 x Generator No. 4C (No. 2A for earlier supplies).
1 x each Bell-gongs Nos. 2 & 2A.
1 x Glass No. 3.
1 x Coil, Induction No. 1, or 12.
1 x Hook, Receiver F.
1 x Receiver, Bell No. 1A.
4 x Cords, Instrument No. 1/16E, Black, 12".
4 x Screws for fixing.
1 x Switch, Receiver No. 3.
1 x Cord, Instrument No. 2/22B, Brown, 33".
1 x Transmitter No. 22 (No.2  for earlier supplies)
1 x Desk No.4, minus backboard.

To be requisitioned separately as required:-
1 x Label No. 78.
1 x Condenser, M.C., No. 102.

The case is held shut by a Lock, Screw No. 1C - renamed as Part No. 3/SLO/17 without spring or 9/SLO/17 with spring.  These fit wood casings " thick.

Made by Ericsson - Model  No's  AB 517 & N20142

Drawing No. 8830.

Circuit diagram - N111.

Additional good quality pictures of the new style set (Mark 238)

Adjustment of Magneto bells

How to convert to Plug and Socket

See also the Telephone Efficiency Committees Report on Local Battery Area telephones.

Diagram for Mark 238 instrument

Early Telephone No. 11
Note the transmitter arm.  This will move up and down whilst keeping the transmitter parallel to the user

 
 
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Last revised: March 12, 2021

FM