Most UK telephone equipment can be identified by the manufacturers codes stamped on them.  All British Post Office equipment is marked in some way and these markings greatly assist in identification and dating.  Even small components are generally marked and these markings will ascertain whether the whole item is in fact genuine.

British Post Office (BPO)
In most cases the markings consist of a description i.e. Tele 232, followed by a manufactures code, followed by a year.
i.e. 1/232L S55 would be a Telephone No. 1/232L, made by Siemens in 1955.  Inside the phone you should see a circuit diagram that should confirm the number on the telephone base.  On 300 type GPO telephones the model number is also printed on the internal chassis - between the bell gongs.

There will almost certainly be a blue stamp near these markings and this would be the GPO quality assurance stamp.

Sometimes these are stamped on a white painted area (the paint covers old stampings).

On wooden apparatus and Candlestick telephones you may find a number crossed out and another number stamped on.  Latter equipment may have a plastic sticker, with the description on, covering the old description.  This is where the apparatus went back to the factory for repair or was made into a different item.  i.e. No. 150 crossed out and No. 156 stamped next to it.

British Ericsson (ETEL)
This company normally prefixed it's part numbers with an N except the very early models.  So on the base expect to see something link N1016.  The part number may be extended i.e. N1016A16, but it's base number is N1016 and the variant of this would be A16.

Inside may be a diagram and these are numbered and they start with N as well.  These diagram numbers DO NOT represent the model or part number and are the diagram number only.  In the Ericsson telephone list you will find that some diagram numbers can be cross referenced.

Check the case for an ETL or Telephone Rentals sticker on the rear.

GEC used a K followed by three or four digits or two letters followed by 4 numbers or a TEL prefix for their telephone part numbers i.e. K7995, IT2201 or TEL23D.  Other products started with a lettered prefix as well.

GEC diagrams are prefixed with KS and these DO NOT represent the model part number.

Want to find a telephone but are completely confused - then follow this link

Some telephone items are reproductions and very good ones at that!  It has been noted that some reproductions even have numbers crossed out on the cases to make them look more authentic.

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Last revised: January 22, 2020