G08B—SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
G08B7/00—Signalling systems according to two or more of groups G08B3/00 - G08B6/00
G08B7/06—Signalling systems according to two or more of groups G08B3/00 - G08B6/00 using electric transmission, e.g. involving audible and visible signalling through the use of sound and light sources
Landscapes
Physics & Mathematics
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General Physics & Mathematics
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Train Traffic Observation, Control, And Security
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