H04M 3/42 Systems providing special services or facilities to subscribers (specially adapted for wireless communication networks H04W4/00)
Introduced: September 1968
Title
Titles differ between systems:
IPC: Systems providing special services or facilities to subscribers
CPC: Systems providing special services or facilities to subscribers (specially adapted for wireless communication networks H04W4/00)
Full Title
Full titles differ between systems:
Automatic or semi-automatic exchanges > Systems providing special services or facilities to subscribers
Automatic or semi-automatic exchanges > Systems providing special services or facilities to subscribers (specially adapted for wireless communication networks H04W4/00)
CPC subdivides this area 2x more granularly than IPC with 17 additional codes.
17 codes are CPC-only extensions.
5 shared codes have differing titles between IPC and CPC.
Child Classifications
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- H04M 3/424 Arrangements for automatic redialling (at the subscriber's set H04M1/27) since 2000 IPC+CPC Available in IPC and CPC
- H04M 3/428 Arrangements for placing incoming calls on hold since 2000 +5 CPC IPC+CPC Available in IPC and CPC
- H04M 3/432 Arrangements for calling a subscriber at a specific time, e.g. morning call service since 2000 IPC+CPC Available in IPC and CPC