DIFF Subgroup
G11B 3/90 with means indicating prior or unauthorised use
Introduced: September 1968
Full Title
Full titles differ between systems:
IPC:
Recording by mechanical cutting, deforming or pressing, e.g. of grooves or pits; Reproducing by mechanical sensing; Record carriers therefor > Record carriers > with means indicating prior or unauthorised use
CPC:
Recording by mechanical cutting, deforming or pressing, e.g. of grooves or pits; Reproducing by mechanical sensing; Record carriers therefor (G11B11/00, take precedence) > Record carriers > with means indicating prior or unauthorised use
No child classifications to compare. This is a leaf node in both IPC and CPC.