Because of the costs of importing products, the company purchased a failing electrical cable factory at North Woolwich in London, in 1898.

In addition to making lead-sheathed cables, the factory started assembling equipment from components imported from Belgium and the US, and subsequently introduced manufacturing.

The buyer of the international operations was the infant ITT Corporation, founded by Sosthenes Behn less than ten years previously with an aggressive and thrusting reputation.

[citation needed] In 1933, Brimar was established to manufacture American-pattern electron tubes at Foots Cray, adjacent to the Kolster-Brandes factory.

Between 1939 and 1945, significant military work was undertaken with many developments particularly with regard to aerial warfare: communications, radar, navigational aids, and especially OBOE The 1950s were characterised by the establishment of television broadcasting.

[4] In the late 1940s and early 1950s, STC also supplied signalbox train describer equipment to British Railways;[5] for the 1949 installation of power signalling in the North and South boxes at Doncaster, STC also provided route setting panels for control of points and signals, using a novel "sequential switch interlocking" format based around telephone exchange switching technology.

In 1966, Charles Kao of STC's Standard Telecommunication Laboratories in Harlow demonstrated that light rather than electricity could be used to transmit speech and (more importantly) data accurately at very high speeds.

Before STC's demise, its plant at Wednesbury Street, Newport came to dominate the recabling of the UK public telephone system.

[9] Before a politically engineered withdrawal in 1982, STC and its (now equally defunct) partners Plessey and GEC, developed the fully digital System X switch which is still in service in the UK as of 2005.

By 1991, with an ageing workforce, loss of business from the newly privatised BT, production spread over too many expensive sites and no clear leadership succession to its former chairman, Sir Kenneth Corfield, STC was bought by Canadian company Northern Telecom (Nortel).