the radar station to L1 and LATCC via microwave links. In the 1960s and 1970s this consisted of processed, but by today's standard raw, video and turning information (i.e. the angle of azimuth of the radar aerial). Received signals from the PD equipment and aerial turning synchronisation information were transmitted over the same links. In the late 1970s, plot extraction equipment was introduced. This took the primary and associated secondary radar outputs, combined and processed them before sending them over telephone lines to the L1. The RPEARDS (Radar Plot Extraction And Remote Display Equipment) was a hard-wired computer that processed, combined and transmitted the signals. Its memory was magnetic core store that had the capacity of some 1000 words, each of over 60 bits in length, and transmission over the telephone line was at 2400 baud using GMSK. Legacy Linesman built on Rotor which had built on Chain Home and the lessons of the Second World War. During the dangerous and tense period that was the Cold War, where the detection and interception of Russian bombers was a weekly, if not daily, event, Linesman enabled the protection and policing of UK air space. IUKADGE and subsequent developments have all built on the legacy of these systems, systems which stem from the Dowding System. An air defence system that enables the quick and accurate deployment of assets to intercept a threat conserves resources and targets them to where they are of the most use. Conceived, proven and tested in the heat of the Battle of Britain, the system is still sound even if the technology has improved many times and the threat since 9/11 has been significantly altered. A spin-off from the Linesman/Mediator work at RSRE Malvern was the invention of the touchscreen in 1965. This was carried out by a team led by E.A Johnson, working in H Building at Malvern. Whilst much of the evidence of Linesman systems and their associated above-ground installations has gone, it is still possible to get a feeling for what operating and working at the height of the Cold War was like at the RAF Air Defence Radar Museum at RAF Neatishead. See also Chain Home Low Air Ministry Experimental Station Comprehensive Display System Type 984 radar Marconi Transistorised Automatic Computer (T.A.C.) References Citations Bibliography External links Radar Type 85 at radarpages.co.uk "Air traffic control in the seventies" – a 1970 Flight article on