Events in telecommunications history
A distinguishing name was given to the telecommunications business of the Post Office - British Telecom - following a Government decision to separate the major Post Office operations. Sir Keith Joseph, Industry Secretary, had announced in the House of Commons in July the Government's intentions to restructure the Post Office and relax the monopoly over terminal equipment and value-added services. However, British Telecom remained part of the Post Office until the following year.
The first of the British-designed processor-controlled digital switching systems designated 'System X' was installed in Baynard House, London. It was a tandem junction unit which switched telephone calls between around 40 exchanges. It was brought into service on 1 July and formally inaugurated in September. The development of 'System X' exchanges was the linchpin of the policy to modernise the existing network by replacing analogue plant with digital switching centres interconnected with digital transmission links. It enabled an increased variety of facilities and services to be made available to the telecommunications user, resulting in ISDN (Integrated Services Digital Network) and ISDN 2 .
The Public Data Packet Switching Service (PSS), a nationwide data network which switches information in the form of individually addressed 'packets' of data, was introduced. PSS proved particularly cost-effective where data transmission was of the intermittent or of the transaction type - for example, point-of-sale terminals, credit verification, communicating word processor or accessing databases both in the UK and overseas. It opened for full commercial operation on 20 August the following year.
The Post Office Tower public restaurant was permanently closed from 14 June for security reasons.
The Prestel service was expanded in October to give greater access nationwide. The Prestel network afforded 62 per cent of telephone subscribers local telephone access to Prestel.
The world's first purpose-designed optical fibre submarine cable, a five nautical mile test loop, was laid in Loch Fyne, Scotland in January.
The first operational optical fibre link in Great Britain went into service between Brownhills and Walsall in the West Midlands, a distance of 9 km..
Two new international telephone exchanges - Mondial and Thames - were opened in London.
The Herald, the first of British Telecom's microprocessor controlled key button systems was introduced in November of this year.
Euronet/Diane, the EEC based information retrieval system, was inaugurated.