DIFF Subgroup
H04R 27/02 Amplifying systems for the deaf
Introduced: September 1968
Full Title
Full titles differ between systems:
IPC:
Public address systems > Amplifying systems for the deaf
CPC:
Public address systems (circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; ; amplifiers H03F) > Amplifying systems for the deaf
No child classifications to compare. This is a leaf node in both IPC and CPC.