STC TELEPHONE No. 4501C TF

No. 4501C TF

These table telephones were supplied for either C.B. and Automatic systems.  The C.B. model could be changed to an automatic model by adding a dial and removing the wire link between terminals T and L2.

Note the 'cats paw' design on the top of the handset rest horns.

Phones can sometimes be dated by the date on the capacitor.

Circuit Diagram - LP29375.

Known to have been used by the Shipton company on internal telephone systems.

Conversion for the UK plug and socket system

1. Remove original line cord.

2. Remove the wire link between terminals E and L1.

3. Fit a 3.3K resistor between terminals E and L1

4. Red wire of new line cord to Terminal L2.

5. White wire of new line cord to Terminal L1.

6. Blue wire of new line cord is unused so insulate with tape.

7. Green wire of new line cord is unused so insulate with tape.

8. Fit a Rectifier Element No. 205 across terminals R and TR.

Circuit Diagram LP39275
 

Pictures
 

The date on the capacitor is 1936

Last revised: August 31, 2024