GEC GECOPHONE
CIRCUIT DIAGRAMS & IDENTIFICATION

Presented here are numerous wiring diagrams and pictures of GEC Gecophones.  As many of these GEC telephones have no part number on the base and no diagram pasted inside, you have to make up your mind which one relates to your telephone.  Under each diagram are instructions on how to wire the telephone up for the UK Plug and Socket system.

Click here for other companies that produced phones similar to the Gecophone and a description of the variants.

The phones can sometimes be dated by reference to the information stamped on the capacitor - which is the oblong component on the base plate.  The capacitors found on many Gecophones will most probably be marked similarly to some of the pictures below.

Most of these telephones come in standard form, but there are also tropicalised models.  The main difference being the mesh over the ringer holes in the base plate and the chunky hook switch neck on the tropicalised models.  As the differences are constructional the wiring diagram would be the same for both a standard and tropicalised telephone of the same type.

C.B. telephones also share the same diagram as their automatic counterpart. The C.B. variant will have a wire link where the dial pulse springs connected, usually shown as a dotted line on diagrams.

A capacitor stamped, for example, with 102 C38/1 2uf will equate as the following:-
The "102" is the capacitor part number, "C38/1" means it was made by GEC in 1938.  "2uf" is the capacitance value.

The telephones below are in circuit diagram number order.  Diagram numbers are not the model number.

GEC Gecophone models K8167 (CB) or K8387 (Automatic)
1930 to 1932
Telephone to Diagram KS7239

This telephone has a single capacitor, a bell and a 4 way terminal block mounted sideways on the base plate.  The body of the phone has a 7 way terminal block and induction coil.  The terminals are labelled with letters and numbers.

The CB variant was supplied without a dial and terminals T and 1 would be linked.

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. White wire of line cord to Bellset terminal L1.
4. A 3.3k resistor is fitted between Bellset terminals L1 and E.
5. Red wire of line cord to Bellset terminal L2.
6. Blue wire of line cord to Bellset terminal C.
7. Green wire of line cord - spare - insulate.
8. Disconnect one of the wires on the 2uf capacitor.
9. Fit a Rectifier element across the receiver on terminals 2 & 3.

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

Single opening on rear for cord entry
 

Probably an early Gecophone as it has an aluminium alloy terminal strip.
 

This model was one of the original Gecophones
Note the early style capacitor with integrated fixings brackets and the large ringer mechanism

On the base there are only two opening to let out the sound of the ringer
As usual - no markings on the base

A view of the end of the capacitor
This was made by GEC in 1933

GEC Gecophone models K8389 (DC Ringer)
1930 to 1934
Telephone to Diagram KS7302

Similar in construction to the K8387, but this telephone has a DC bell.  It also has an electromagnetic-receiver.  This telephone has no induction coil or capacitor.  The handset cord has two wires only.

Due to the electromagnetic-receiver the line is polarity conscious.

The base has a single bell gong, the bell clapper mechanism and an upright, 4 way, Paxolin terminal block.

There are no components in the case, except the switch hook contacts, which consists of a make contact set and a changeover contact set.

This telephone cannot be converted on the UK telephone network and was probably used on internal telephone systems.

The same diagram is probably used with the Telephone No. 90.

GEC Gecophone model K8389 (DC)
1930 to 1932
Telephone to diagram KS7533

The telephone has a DC dome type bell and was used on the PX1110 or PX1210 PAX system.   It also has an electromagnetic-receiver.  This telephone has no induction coil or capacitor.  The handset cord has two wires only.

Due to the electromagnetic-receiver the line is polarity conscious.

This telephone cannot be converted to work on the UK telephone network.

GEC Gecophone Magneto
Model unknown
Telephone to Diagram KS7450

Gecophone, Magneto

Circuit Diagram KS7450

Click here for more pictures

GEC Gecophone model 75 (Automatic) and 175 (CB)
1932 to 1948
Telephone to Diagram KS7549 (Irish P&T TX1195)

This telephone has a single capacitor, a bell and a 4 way terminal block mounted on the base plate.  The body of the phone has a 8 way terminal block and a 6 tag induction coil.   Note there are now two cord entry points: the entry hole in the case is for the handset cord and line cord enters via the ferrule that is fixed to the base plate.

This construction probably ran until 1955, with just the model number changing as GEC renumbered the ranges at certain points.

The CB telephone, the Model No. 175,would have the dial missing and terminals 3 and 4 linked together.

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 base plate entry hole and tie it or knot it to the terminal upstand.
3. Remove wire strap between Bellset terminals L1 and E.
4. White wire of line cord to Bellset terminal L1.
5. A 3.3k resistor is fitted between Bellset terminals L1 and E.
6. Red wire of line cord to terminal Bellset L2.
7. Blue wire of line cord to terminal Bellset C.
8. Green wire of line cord - spare - insulate.
9. Disconnect one of the wires on the 2uf capacitor and insulate.
10. Fit a Rectifier element across the receiver on terminals 5 & 6.

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

Made in 1939 the telephone in the following pictures is a Model 175 (CB)
The model 75 is exactly the same except it is fitted with a dial
 

Rear of phone showing the two entry points

Internal view showing the newly designed 7 terminal Induction Coil.
The terminal block is 8 way and terminals 3 and 4 are linked as this telephone has no dial.

Base plate changes from the original design include the terminal block placed above the bell, a ringer
of a much reduced size, different fixing for the capacitor and the line cord entry ferrule.

Capacitor showing the telephone was produced in 1938 by GEC

Base plate with cord ferrule and four ringer sound exit holes in place of the original single sound exit holes.
Note the feet on this phone are made of cork.

This is a model 175 and was supplied to the Gleneagles Hotel in Scotland. 

The telephones were originally installed in 1933/1934 and dumped during a 1974 refurbishment.

This picture is the model 75

 

GEC Gecophone model 75 (Automatic) and 175 (CB)
1932 to 1948
Telephone to Diagram KS8197

 

 

 

This telephone has a single capacitor, a bell or buzzer and a 4 way terminal block mounted above the bell ringer.  The body of the phone has a 6 way terminal block and 7 tag induction coil (DRG 52381).  Although the terminal block has 8 holes only 6 are populated with terminals

It could be supplied with a bell ringer or buzzer.

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 base plate entry hole and tie it or knot it to the terminal upstand.
3. White wire of line cord to Bellset terminal L1.
4. A 3.3k resistor fitted between Bellset terminals L1 and E.
5. Red wire of line cord to Bellset terminal L2.
6. Blue wire of line cord to Bellset terminal C.
7. Green wire of line cord - spare - insulate.
8. Disconnect one of the wires on the 2uf capacitor.

9. Check transmission and replace transmitter if bad and always fit a Rectifier element across the receiver on terminals 6 & 5.  Click here for more information.

 

GEC Gecophone model ST1301 and ST1401 & ST1406 (sound holes covered with mesh)
1948 to 1955
Telephone to Diagram KS8548

Rear view showing two entry points

Telephone model ST1301 has a base plate with holes that have no mesh, whilst
the ST1401 has a base plate with holes covered with mesh.
A phone with mesh covers over the sound holes is a tropicalised version - ST1406 above.

Internal view of the body exposing the angled contact switch set fitted to Tropicalised variants.
Probably an ST1406

Internal view of the base plate showing the AC buzzer.
Buzzers were fitted instead of bells when used in ships cabins.
This is probably an ST1406

Capacitor is dated 1948 and made by GEC

A CB variant is pictured above which always comes without a dial and therefore terminals 3 and 4 will be linked together.  The pictures show that it was supplied with an AC buzzer, but a bell could also be specified.  This telephone would have been supplied for hotel or ships cabin use.

The is fitted with a 6 way terminal block and a 7 tag Induction Coil.

Diagram KS8548
The diagram shows a plug ended line cord, which were used on ships and in hotels
This diagram covers 6 terminal models of the ST13XX, ST14XX, ST1603 onwards, ST 1503 and ST1504 models

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 base plate entry hole and tie it or knot it to the terminal upstand.
3. Remove wire strap between Bellset terminals L1 and E
4. A 3.3k resistor is fitted between Bellset terminals L1 and E.
5. White wire of line cord to Bellset terminal L1.
6. Red wire of line cord to terminal Bellset L2.
7. Blue wire of line cord to terminal Bellset C.
8. Green wire of line cord - spare - insulate.
9. Disconnect one of the wires on the 2uf capacitor 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.

GEC Gecophone model ST1301, ST 1302, ST1401, ST1402, ST1503, ST 1304, ST1510, ST1603 and ST1610
1948 to 1955
Telephone to Diagram KS10208 (Irish P&T Diagram KX2794)

Telephone model ST1301, ST1503 & ST1510 (open base plate holes) and
Telephones ST1401, ST 1402, ST1603 & ST1610 (base plate holes covered with mesh)
Note the 7 tag Induction Coil

Internal picture showing the angled contact set fitted to Tropicalised variants

The pictures shows a telephone made in 1951, but the base plate is like most models made from 1934 to 1955.
The bell holes have mesh covering them so this is a tropicalised variant.
This telephone is the ST1610 which was made for ship cabin use and has an AC buzzer fitted instead of a bell.

 

Base plate showing mesh covered sound holes, which are only on Tropicalised models

This telephone has a single capacitor, a bell or buzzer and a 4 way terminal block mounted on the base plate.  The body of the phone has a 8 way terminal block and induction coil with seven tags.  The Tropicalised models have an contact set which is mounted at an angle to the terminals and mesh covers on the sound exit holes (in the base plate).

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 base plate entry hole and tie it or knot it to the terminal upstand.

3. Remove wire strap between Bellset terminals L1 and E

4. White wire of line cord to Bellset terminal L1.

5. A 3.3k resistor fitted between Bellset terminals L1 and E.

6. Red wire of line cord to terminal Bellset L2.

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

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

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

10. Fit a Rectifier element across the receiver on terminals 5 & 6.

11. Check transmission and replace transmitter if bad.

GEC Gecophone model TEL/32G/ATT
Called the Gecophone "K" or Gecophone 1000
1956
Diagram - KS10915
It is not known if this model was produced in any great number

Major changes to this Gecophone were the handset, a 4 way handset cord,
new Induction Coil, two capacitors and a 5 way terminal strip on the base plate

One capacitor is on the base plate whilst the other is squeezed into the body
The feet are also a push fit

Diagram KS10915

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. White wire of line cord to Bellset terminal 2.
4. A 3.3k resistor fitted between Bellset terminals 2 and 3.
5. Red wire of line cord to terminal Bellset 4.
6. Blue wire of line cord to terminal Bellset 5.
7. Green wire of line cord - spare - connect the Bellset terminal 1.
8. Disconnect one of the wires on the 2uf capacitor and insulate.
9. Fit a Rectifier element across the receiver on telephone terminals 7 and 6.
10. Check transmission and replace transmitter if bad - Click here for more information.

Last revised: August 30, 2025