Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Publication of NL60456CpublicationCriticalpatent/NL60456C/xx
H04Q1/00—Details of selecting apparatus or arrangements
H04Q1/18—Electrical details
H04Q1/30—Signalling arrangements; Manipulation of signalling currents
H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
H04Q1/442—Signalling arrangements; Manipulation of signalling currents using alternate current with out-of-voice band signalling frequencies
H04Q1/4423—Signalling arrangements; Manipulation of signalling currents using alternate current with out-of-voice band signalling frequencies using one signalling frequency
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04B—TRANSMISSION
H04B3/00—Line transmission systems
H04B3/02—Details
H04B3/42—Circuits for by-passing of ringing signals