Pre-2000 type, 6-bank 2-motion group selector switch, 1960-1975.
© Science Museum / Science & Society Picture Library
From the 1890s to the 1950s, the method of switch selection introduced by Almon Brown Strowger (1839-1902) dominated automatic telephony. This part is from Strowger electromechanical selector and director equipment previously in use at the British Telecom's Deptford exchange in Greater London. The Strowger equipment was removed in December 1990 following the growth of digital exchanges.