Arrangements for detecting or preventing errors in the information received

Introduced: September 1968

Of 11 combined children, 6 exist in both systems.

5 codes are CPC-only extensions.

Note: 2 CPC extensions are marked as secondary classification only.

1 shared codes have differing titles between IPC and CPC.

Child Classifications

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H04L 1/0001 +8 CPC CPC only CPC only
H04L 1/004 +6 CPC CPC only CPC only
H04L 1/0078 +7 CPC CPC only CPC only
H04L 1/02 by diversity reception IPC+CPC Available in IPC and CPC
H04L 1/08 by repeating transmission, e.g. Verdan system IPC+CPC Available in IPC and CPC
H04L 1/12 by using return channel +1 CPC IPC+CPC Available in IPC and CPC
H04L 1/20 using signal quality detector since 1980 +5 CPC IPC+CPC Available in IPC and CPC
H04L 1/22 using redundant apparatus to increase reliability since 1980 IPC+CPC Available in IPC and CPC
H04L 1/24 Testing correct operation since 1980 +4 CPC IPC+CPC Available in IPC and CPC
H04L 2001/0092 2nd only +5 CPC CPC only CPC only
H04L 2001/0098 2nd only CPC only CPC only

Class H04,2013–2023, worldwide · Source: EPO PATSTAT

Class H04,2013–2023, worldwide · Source: EPO PATSTAT