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Filing date
Publication date
Application filedfiledCritical
Publication of NL6916697ApublicationCriticalpatent/NL6916697A/xx
H04M1/00—Substation equipment, e.g. for use by subscribers
H04M1/26—Devices for calling a subscriber
H04M1/30—Devices which can set up and transmit only one digit at a time
H04M1/50—Devices which can set up and transmit only one digit at a time by generating or selecting currents of predetermined frequencies or combinations of frequencies
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04Q—SELECTING
H04Q3/00—Selecting arrangements
H04Q3/0004—Selecting arrangements using crossbar selectors in the switching stages