British Telecom (BT) Test and Service Cards, including Test Cards 1A and 3A.
BTT001 - Test Card 1A - handwritten voltages - Control number: 497 306
Landis and Gyr Software Testkarte for STU 07 (Structure 7) Great Britain - Control number: 112L00020
BTT005 Test Card without any printed numbers/values
BTT002 Matt Test Card
BT Test Card
Selection of British Telecom Test Cards