Standard CBS No. 1 wall telephone with no magneto generator.

This is a wooden Local Battery telephone with sloping writing shelf and paper clip.  Two batteries were housed in the bottom of the case.  Two "Cells, Leclanché, 2 block, Agglomerate, complete" batteries would be fitted.

Previously known in 1905 as the "Telephone, Wall, with Magneto Bell complete".

The set shown to the right was an early model made by Ericsson.  The Transmitter arm moved up and down.

A Coin Collecting Box could be fitted to the CB terminals on the telephone.

An additional receiver can be fitted on the right hand side of the telephone.

A later version was produced, the Mark 238, which was oblong in shape (see pictures below).

This telephone was in the 1928 Rate book but not available in the 1946 Rate Book.

Fitted with a Transmitter No. 2 although earlier types had a Transmitter No. 6.

If a Transmitter No. 2 was fitted then a Label No. 78 was fitted between the speaking tube and the transmitter body.  This label advised of the Exchange name and number.

The bell coils are wired in parallel, so as to offer a resistance of 250ohms.

This telephone could also work on CBS No. 2 & 3 exchanges by the addition of a 2uf capacitor (Condenser M.C. No. 22).

In 1906, Diagram CBS141 explains the arrangements for provincial party lines with two to ten parties.  In this system X subscribers 1, 2 ,3 ,4 and 5 would be called by ringing the A leg to earth, whilst the Y subscribers 1, 2, 3, 4 and 5 would be rung on the B leg to earth.  In early directories a subscriber number on a party line would be described thus: 238Y5 - 238 being the line number, to be rung on the B wire, five times.

When used on party lines the "Coil, Induction 25/1" is replaced by a "Coil, Induction 150/1".

This telephone is superseded by the Telephone No. 15 if used with a Bellset No. 7.

The Telephone No. 11 was the Magneto equivalent.

Mark 238 Telephone includes (1928):-
1 x Arm, Transmitter No. 1.
1 x Bell No. 1A, unmounted. (Earlier types had Bells No. 9A).
1 x Coil, Induction No. 1 (Earlier types) or No. 12 (Mark 238).
4 x Cords, Instrument No. 1/16E, Black, 12".
1 x Cord, Instrument No. 2/22B, Brown, 33".
2 x Plates, Connection, No. 1.
6 x Plates, Connection, No. 6.
10 x Plates, Connection, No. 7.
4 x Plates, Connection, No. 8.
1 x Plate, Escutcheon, No. 3.
1 x Plate, Escutcheon, No. 7.
1 x Frame, Notice No. 1 (Earlier types had Frame, Notice No. 2 and Label No. 53B) .
1 x Glass No. 3.
1 x Switch, Receiver No. 3.
1 x Hook, Receiver F.
1 x Transmitter No. 2. (Earlier types had Transmitter No. 6).
1 x Mouthpiece No. 16.
1 x Receiver, Bell No. 2 (Earlier types) or Receiver, Bell No. 1A (Mark 238).
1 x Desk No.4, minus backboard.
4 x Fixing screws.

For earlier supplies:-
1 x Bell No. 9A (Ericsson).
1 x Coil, Inductor 25/1.
1 x Transmitter No. 6.
2 x Cord, Flexible No. 116.
1 x Cord, Flexible No. 222.
1 x Receiver, Bell A or No. 2.
1 x Label No. 53B or Card TE 130.

Frames, Notice No. 2 and Labels No. 53B were not maintained in the old type of these instruments.

Circuit diagram - N103.

Drawings - 8830, 8831 & 8832 (All Mark 238 and dated 1929).

Drawing for the desk - 7437.

Specification - D150.

Supplied by Ericsson, their Model N20141 (Mark 238 - Dated 1932).

GPO instructions state that this telephone should be fixed to the wall with it's lower edge 36 inches from the floor.

Later version, the Mark 238
Inside the telephone - the silver cylindrical object, to the right,
is a modern style capacitor

Diagram for Mark 238 instrument
BACK Home page BT/GPO Telephones Search the Site Glossary of Telecom Terminology Quick Find All Telephone Systems

Last revised: January 19, 2024