Subscriber information was programmed into the exchange in racks called cyclic stores which used PTFE wire threaded through magnetic cores known as 'Dimond ring' (see TXE2 section for more information). The information stored was the class of service (COS) i.e. PBX, coin collecting box (CCB) or single line, followed by the directory number. The subscribers derived an equipment number from the position on the cyclic store rack. This was a six-digit number and referred to as the MUCKBL. In some parts of the exchange, equipment was in the format of BUMCLK. When a subscriber lifted their handset it sent a pulse down this wire, which was picked up by a 156 ms scanner, which set up a path through the reed relays to a register. This register then returned dialling tone to the subscriber and dialling could commence.