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.)
NEC Corp
Original Assignee
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 Nippon Electric Co LtdfiledCriticalNippon Electric Co Ltd
Priority to JP10465779ApriorityCriticalpatent/JPS5628587A/ja
Publication of JPS5628587ApublicationCriticalpatent/JPS5628587A/ja
Publication of JPS6230556B2publicationCriticalpatent/JPS6230556B2/ja
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
H04Q1/444—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies
H04Q1/45—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using multi-frequency signalling
H04Q1/453—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using multi-frequency signalling in which m-out-of-n signalling frequencies are transmitted
Landscapes
Engineering & Computer Science
(AREA)
Computer Networks & Wireless Communication
(AREA)
Digital Transmission Methods That Use Modulated Carrier Waves
(AREA)
JP10465779A1979-08-171979-08-17Multifrequency signal detection system
GrantedJPS5628587A
(en)