CPC Subgroup
H04Q 1/442 with out-of-voice band signalling frequencies
Full Title
Details of selecting apparatus or arrangements > Electrical details > Signalling arrangements; Manipulation of signalling currents (multiplex systems providing for calling or supervisory signals H04J1/14, H04J3/12) > using alternate current (H04Q1/50 takes precedence) > with out-of-voice band signalling frequencies
2 direct subcodes
Child Classifications
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