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 NL66179CpublicationCriticalpatent/NL66179C/xx
H04M7/00—Arrangements for interconnection between switching centres
H04M7/16—Arrangements for interconnection between switching centres in systems employing carrier frequencies
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04J—MULTIPLEX COMMUNICATION
H04J1/00—Frequency-division multiplex systems
H04J1/02—Details
H04J1/14—Arrangements providing for calling or supervisory signals
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04Q—SELECTING
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