Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AgfiledCriticalSiemens Ag
Application grantedgrantedCritical
Publication of AT182680BpublicationCriticalpatent/AT182680B/de
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