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G04C21/00—Producing acoustic time signals by electrical means
G04C21/16—Producing acoustic time signals by electrical means producing the signals at adjustable fixed times
G04C21/30—Producing acoustic time signals by electrical means producing the signals at adjustable fixed times with provision for a number of operations at different times, e.g. ringing the bells in a school
G—PHYSICS
G04—HOROLOGY
G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
G04C21/00—Producing acoustic time signals by electrical means
G04C21/16—Producing acoustic time signals by electrical means producing the signals at adjustable fixed times
G04C21/20—Producing acoustic time signals by electrical means producing the signals at adjustable fixed times by closing a contact to ring an electromechanical alarm