An equipment practice was needed quickly, and it was realised that a matrix of reed relays would be about the same size as a crossbar switch. Therefore, the equipment practice of AT&E's crossbar system was adopted for the TXE1 apart from the common control, which had its own equipment practice. The common control consisted of 14 racks and made up a complete suite of the exchange. It was made entirely from discrete components as integrated circuits were not yet in common use. There was much discussion by all contractors as to whether there was a reliable connector available to make units interchangeable. STC decided to have the units that could be withdrawn and AT&E and AEI did not. It turned out that the connectors used were reliable and they had a great advantage in fault finding. It also allowed the STC engineers to place a suspect faulty unit in an outrigger so it could be tested in situ.