CPC Main Group
G04C 21/00 Producing acoustic time signals by electrical means
3 direct subcodes
Child Classifications
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- G04C 21/02 Constructional details (G04C21/04, G04C21/16 take precedence)
- G04C 21/04 Indicating the time of the day
- G04C 21/16 producing the signals at adjustable fixed times