Phonecards with a 'shifted' control number

British Telecom (BT) telephone cards produced by Landis & Gyr between 1981 and 1996 all feature a control number on the reverse. What is a control number? Learn more here.

The common and correct position for the control number is on the reverse of the BT Phonecard in the bottom right hand corner (as you turn the card over like the page of a book) and close to the edge or margins of the Phonecard.

A 'shifted' control number doesn't appear in this correct position, but instead is 'shifted' further left towards the centre of the Phonecard. Often the shift may only be a centimetres, but sometimes in more rare cases, the shift sees the control number move to the centre of the base of the telephone card or beyond!

Shifted control numbers were caused by the stamping process of the control number by the machine producing telephone cards in the Landis & Gyr factory.

The reverse corner of the BT Phonecard pictured below on the left has the control number in the correct position, while the reverse corner of the BT Phonecard pictured below on the right has a shifted control number.

Circled below in red, a seriously shifted control number. The control number has been imprinted onto the reverse side of the card a long way to the left. The control number on this card is almost in the centre of the Phonecard.

Circled below in red, another shifted control number. This control number is in fact closer to the left hand edge of the card, when it should be close to the right hand edge of the telephone card!


Optical Phonecard Control Numbers: Further Reading

For further information about Landis & Gyr optical telephone card control numbers you may find the following links useful:

What is a Phonecard control number?
Phonecards without a control number
Phonecards with a '999' prefix control number
Phonecards with a 'shifted' control number

Pictured above - BT Phonecard Definitive 1st issue 200unit with a 'split' control number on the reverse.

Do you have a optical BT Phonecard with a shifted control number? I'd be keen to hear from you, please contact me and tell me more about the card, or better still, send over a photo or scan of both sides of the telephone card.

Plus if you are a collector and would like to contribute content, images or information to this page, please also contact me.


The two latest catalogues (UK 1 BT Optical Cards is pictured right) which together feature all of BT Phonecards and catalogue numbers can be viewed and purchased here.

Last updated: 14th July 2017

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