TMC produced the compact style telephone and the cases are exactly the same as ETL compacts.  Later, TMC did start to use cases similar to the GEC type.

The case itself just contains the dial and the base plate is normally populated with the components.

TMC cases normally have two cable entry holes in the rear, which have ebonite grommets.  Some cases, however, have been seen with a single cable entry.  TMC also made these phones for Telephone Rental and some of these have base plates which have been found with a set of 9 holes, in a circle, under each gong (as do Ericsson compacts).

Many compacts found have a cylindrical capacitor.  These capacitors were introduced in the UK circa 1955.

These phones can sometimes be dated by looking at the markings on the capacitor.

Click here for more information on compact telephones.

The information below show unknown models with unknown diagrams.  Any information of these would be gratefully received.



This is a Compact made for Telephone Rentals in 1950

TMC produced this compact telephone for Telephone Rentals.  They normally have no part number on the base and no number on the internal diagram.

The telephone has a basic GPO circuit with all the components in one body.  These can be easily converted to work in the UK.

It has two capacitors (in the same casing), an induction coil and a bell on the base plate.  In the body of the phone is an 8 way terminal array with a 6 way terminal block on the base plate.  This is slightly unusual for TMC Compacts which generally do not have a terminal block on the base plate.

The base plate is stamped with 18 sounds holes and the case has elongated corners (the same as an Ericsson).  See below for a picture.

The capacitor is square whereas GEC and Ericsson used oblong capacitors.  These capacitors are dated.

Front view
This example has rotten switch hooks, which are all droopy!


TR markings on rear of case
Telephone Rentals retained ownership of all equipment they rented


Inside the case - standard GPO induction coil
The dial on this example is an ATM No. 24, which is believed to have been retrofitted whilst in service


Base plate showing 6 way terminal block and square capacitor
The base plate is shaped as per an Ericsson Compact


Base plate
Note that the base plate is extended at the corners


Ericsson Compact Base plate
No sounds holes but most have 18 holes.
Note the position of the two oblong punched lugs.
They are just above the central hole.
These help retain the oblong capacitor.
Two threads, close together, showing centre
right - these fixed the small terminal block
TMC/TR Compact Base plate
18 sound holes.
Note the position of the two oblong punched lugs.
They are away from the central hole.
These help retain the square capacitor.
Two threads, far apart, showing centre
right - these fixed the long terminal block

Circuit diagram


To convert to UK plug and socket use a BT line cord and wire as follows:-

  1. Remove and discard the old line cord.

  2. Feed the new line cord through the casing entry hole and tie it or knot it to the metal loop inside the phone.

  3. Remove wire strap between Bellset terminals 5 and 6

  4. White wire of line cord to Bellset terminal 6.

  5. A 3.3k resistor fitted between Bellset terminals 5 and 6.

  6. Red wire of line cord to terminal Bellset 4.

  7. Blue wire of line cord to terminal Bellset 3.

  8. Green wire of line cord - spare - insulate.

  9. Disconnect one of the wires on the 2uf capacitor - the green wire and insulate.

  10. Fit a Rectifier element across the receiver on terminals 1 & 2.

  11. Check transmission and replace transmitter if bad - Click here for more information.


Compact dated later than 1955

Note Ericsson style case



Note the induction coil is mounted on the base plate.
There are no mounting holes in the casing to fit one.


Note Ericsson case but it has a square edged base plate



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Last revised: January 07, 2023