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.)
Lignes Telegraphiques et Telephoniques LTT SA
Original Assignee
Lignes Telegraphiques et Telephoniques LTT SA
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Filing date
Publication date
Application filed by Lignes Telegraphiques et Telephoniques LTT SAfiledCriticalLignes Telegraphiques et Telephoniques LTT SA
Priority to FR7413137ApriorityCriticalpatent/FR2268406A1/fr
Publication of FR2268406A1publicationCriticalpatent/FR2268406A1/fr
Application grantedgrantedCritical
Publication of FR2268406B1publicationCriticalpatent/FR2268406B1/fr
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
H04Q1/46—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies comprising means for distinguishing between a signalling current of predetermined frequency and a complex current containing that frequency, e.g. speech current
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Engineering & Computer Science
(AREA)
Computer Networks & Wireless Communication
(AREA)
Devices For Supply Of Signal Current
(AREA)
FR7413137A1974-04-161974-04-16Double frequency telephone signalling - recognises signal for set frequency voltage relationship
GrantedFR2268406A1
(en)
