GEC GECOPHONE
CIRCUIT DIAGRAMS & IDENTIFICATION

Click here for other companies that produced phones similar to the Gecophone.

They can be dated by reference to the information stamped on the capacitor (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, 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 rest on the tropicalised models.  The wiring diagram would the same for both type.

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

GEC Gecophone models K8167 (CB) or K8387 (Automatic)
1930 to 1934
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 or 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 and therefore requires no induction coil.  The handset cord has two wires only.

This telephone cannot be converted and was probably used on internal intercom systems.

GEC Gecophone model K8389 (DC)
1948 to 1955
Telephone to diagram KS7533

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

This telephone cannot be converted.

GEC Gecophone model 75 (Automatic) and 175 (CB)
1934 to 1948
Telephone to Diagram KS7549

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 or 7 tag induction coil.   Note there are now two cord entry points, the lower entry point is via a 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 model 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 ferrule and four ringer sound exit holes in place of the original single sound exit holes

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.

The picture below is the model 75

Telephone to Diagram KS8197

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 6 way terminal block and 6 tag induction coil.

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 (sound holes covered with mesh)
1948 to 1955
Telephone to Diagram KS8548

Rear view showing two entry points

Telephone model ST1301 (open base plate holes) and ST1401 (base plate holes covered with mesh)

Internal view of the body exposing the angled contact switch set.

Internal view of the base plate showing the AC buzzer

Capacitor is dated 1948 and made by GEC

This is a CB variant with no 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 use.

The is fitted with a 6 way terminal block and a 7 tag Induction Coil.  The contact switch is at an angle.

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 ST1503 and ST1603
1948 to 1955
Telephone to Diagram KS10208

Telephone model ST1503 (open base plate holes) and ST1603 (base plate holes covered with mesh)

Internal picture showing the angled contact set

The pictures show 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 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.  This model also has an usual contact set which is mounted at an angle to the terminals.

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
Telephone to Diagram - KS10915
It is not known if this model was produced

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 & 6.

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

Last revised: January 24, 2022