DIFF Subgroup
G04B 19/20 Indicating by numbered bands, drums, discs, or sheets
Introduced: September 1968
Full Title
Full titles differ between systems:
IPC:
Indicating the time by visual means > Indicating by numbered bands, drums, discs, or sheets
CPC:
Indicating the time by visual means ( by electric lamps G04C17/02; display arrangements in general G09F) > Indicating by numbered bands, drums, discs, or sheets
CPC subdivides this area 4x more granularly than IPC with 3 additional codes.
3 codes are CPC-only extensions.
IPC defines codes here since 1980.
Child Classifications
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