DIFF Subgroup
H04Q 1/18 Electrical details
Introduced: September 1968
Full Title
Details of selecting apparatus or arrangements > Electrical details
IPC and CPC are identically structured here. All 5 subcodes exist in both systems.
3 shared codes have differing titles between IPC and CPC.
Child Classifications
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- H04Q 1/20 Testing circuits or apparatus; Circuits or apparatus for detecting, indicating, or signalling faults or troubles IPC+CPC Available in IPC and CPC
- H04Q 1/28 Current-supply circuits or arrangements for selection equipment at exchanges IPC+CPC Available in IPC and CPC
- H04Q 1/30 Signalling arrangements; Manipulation of signalling currents (multiplex systems providing for calling or supervisory signals H04J1/14, H04J3/12) IPC+CPC Available in IPC and CPC
- H04Q 1/54 Amplifier switched-on automatically in dependence on automatically-selected lines IPC+CPC Available in IPC and CPC
- H04Q 1/56 Balancing circuitry switched-on automatically in dependence on automatically-selected lines IPC+CPC Available in IPC and CPC