Royal Observer Corps
The Royal Observer Corps (ROC) was a civil defence organisation intended for the visual detection, identification, tracking and reporting of aircraft over Great Britain. It operated in the United Kingdom between 29 October 1925 and 31 December 1995, when the Corps' civilian volunteers were stood down. (ROC headquarters staff at RAF Bentley Priory stood down on 31 March 1996). Composed mainly of civilian spare-time volunteers, ROC personnel wore a Royal Air Force (RAF) style uniform and latterly came under the administrative control of RAF Strike Command and the operational control of the Home Office. Civilian volunteers were trained and administered by a small cadre of professional full-time officers under the command of the Commandant Royal Observer Corps; latterly a serving RAF Air Commodore.
Royal Observer Corps
Inter-group control-to-control exchange of burst and radiation data was initially via "teller" voice message using telephone lines between adjacent groups. In 1971 this method was replaced by punched tape data exchanges by telegraph teleprinters located in the communications centre. Between 1981 and 1985 the teleprinters were replaced with modern computerised AD9000 message switch equipment, operating over a permanent and EMP hardened landline network, permitting direct communications between groups nationally. In the late 1980s the manually operated PMBX switchboards were replaced with computerised direct dial SX2000 equipment.
During the years immediately prior to the stand down of the ROC, trials were undertaken with the intention of providing monitoring posts with remotely operated above ground petrol generators to provide a constant electricity supply (a portable generator capable of producing both 12 V and 240 V(Yamaha EF1000) was supplied in small quantities to a number of groups), "black" heaters to provide a warmer environment and new sealed, recycling ventilators to allow air changes without requiring the post to be exposed to a contaminated air source.