STC TELEPHONE No. 4509

This is a standard British Post Office telephone set (Telephone No. 332).  It is a self-contained micro-telephone set with ringer housed in the case.  Supplied complete with cords and moulded terminal block.

The micro-telephone incorporates the high quality receiver giving a gain of intelligibility equivalent to about 5db.

The set is constructed of moulded Bakelite and the standard colour is black.

An anti-side tone circuit is used so that extraneous noises in the vicinity of the listener cause minimum interference with the reception of speech.

Unless otherwise ordered Dial No. 4002-AG, showing numbers only on the number plate, will be supplied with these sets.  Number plates with any other type of marking can be supplied if a sample or drawing is submitted.

The No. 4509-A and 4509-C sets are similar but the dial is replaced by an apparatus blank. A dial can be fitted at a later date if required.

4509-A and B Sets are fitted with a Directory Tray.

4509-C, D and J Sets do not include a Directory Tray.

Taken from:-
STC Apparatus Catalogue for Telephone, Remote Control and Railway Signalling Catalogue, Edition 5 (1952)

These telephones would have been supplied to private companies for use on internal automatic telephone systems.

Some manual models have been converted to automatic by the addition of a dial.

These have also been seen with LP14226 & LP14230 (4509BG) markings, which may be diagram numbers.

The 4509C has been seen with a press button and dial.  The dial will be a retrofit as the telephone is prewired for a dial.

See also British Ericsson Telephone No. N1005A.

4509D

Last revised: July 26, 2025