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PCE
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DIFF Subgroup
H04M 3/08

Indicating faults in circuits or apparatus

Introduced: September 1968

Full Title

Automatic or semi-automatic exchanges > Indicating faults in circuits or apparatus

Of 4 combined children, 3 exist in both systems.

1 codes are CPC-only extensions.

Child Classifications

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  • H04M 3/085 CPC only CPC only
  • H04M 3/10 Providing fault- or trouble-signals IPC+CPC Available in IPC and CPC
  • H04M 3/12 Marking faulty circuits "busy"; Enabling equipment to disengage itself from faulty circuits IPC+CPC Available in IPC and CPC
  • H04M 3/14 Signalling existence of persistent "off-hook" condition IPC+CPC Available in IPC and CPC