| 968 / | HD | HOROLOGY |
| 968 | DD | PRODUCING ACOUSTIC TIME SIGNALS [G04G 13/00] {1} |
| 969 | | .~ At preselected times, e.g., alarm clocks, etc. [G04G 13/02] {4} |
| 970 | DD | .~.~> Details [G04G 13/02A] {1} |
| 972 | DD | .~.~> Acting only at one preselected time [G04G 13/02B] |
| 973 | DD | .~.~> Acting at a number of different times [G04G 13/02C] |
| 974 | DD | .~.~> Combined with a radio [G04G 13/02D] |