Legal status (The legal status 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 status listed.)
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujitsu Ltd
Hitachi Ltd
NEC Corp
Nippon Telegraph and Telephone Corp
Oki Electric Industry Co Ltd
Original Assignee
Fujitsu Ltd
Hitachi Ltd
Nippon Telegraph and Telephone Corp
Oki Electric Industry Co Ltd
Nippon Electric Co Ltd
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.)
Filing date
Publication date
Application filed by Fujitsu Ltd, Hitachi Ltd, Nippon Telegraph and Telephone Corp, Oki Electric Industry Co Ltd, Nippon Electric Co LtdfiledCriticalFujitsu Ltd
Priority to JP56197069ApriorityCriticalpatent/JPS5897957A/ja
Publication of JPS5897957ApublicationCriticalpatent/JPS5897957A/ja
Publication of JPH0210638B2publicationCriticalpatent/JPH0210638B2/ja
H04Q1/00—Details of selecting apparatus or arrangements
H04Q1/18—Electrical details
H04Q1/30—Signalling arrangements; Manipulation of signalling currents
H04Q1/38—Signalling arrangements; Manipulation of signalling currents using combinations of direct currents of different amplitudes or polarities over line conductors or combination of line conductors