| 968 / | HD | HOROLOGY |
| 580 | DD | PRODUCING ACOUSTIC TIME SIGNALS BY ELECTRICAL MEANS (for mechanical clocks or watches subclasses 225 and 243) [G04C 21/00] {3} |
| 582 | DD | .~ Indicating the time of the day (acoustic indication of time subclass 217) [G04C 21/04] {2} |
| 586 | | .~.~ By electro-acoustic time means [G04C 21/12] {1} |
| 587 | DD | .~.~.~> Electro-acoustic time announcement, i.e., spoken [G04C 21/14] |