MOTORWAY COMMUNICATION SYSTEMS | ||||||||
| In the 1960's and early
1970's the GPO were asked to provide communication systems for some of the
UK's newly introduced motorways (M1 and M4). The GPO supplied telephones, cable and terminating equipment at control centres. These systems were VF (1500, 1740, 1980, 2220 and 2460c/s frequencies were used) and connected roadside cabinets to a control centre. There was no connection to the public network and calls could only be made from the cabinet to the control centre. The system was effectively a 10 station party line and each telephone could be identified at the control centre by a lamp. The system at the cabinet was powered by three Batteries, Dry DS6, two Batteries, Dry No. 29 and three Batteries, Dry No. 33. Signalling was sent from each cabinet by means of two oscillators (Oscillators No. 93) and a pulse unit. Each of the 10 stations were allocated their own particular combination of two frequencies. The pulse unit was just a timing device that connected the Oscillators to line for 2 seconds. The system was activated by a switch in the telephone and a door switch on the cabinet. General information - B3 C0661. General Information - C3K6001.
The cabinets were provided and installed by the Department of the
Environment |
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Last revised:FM2 | ||||||||
