Arrangements producing acoustic signals at preselected times

Official title: Arrangements producing acoustic signals at preselected times {(indicating the time by optical means G04B19/00, G04C17/00; indicating the time by acoustic means G04B21/00; indicating the time by means other than acoustic or optical, or by a combination of means G04B25/00; acoustic time signals produced electrically G04C21/00; coin-freed alarm clocks G07F17/0007; acoustic signalling means G08B3/00)}

G04B23/00 (Arrangements producing acoustic signals at preselected times) appears on 174 US grants and 117 published applications in this corpus.