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.)
Individual
Original Assignee
Individual
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 IndividualfiledCriticalIndividual
Application grantedgrantedCritical
Publication of FR468891ApublicationCriticalpatent/FR468891A/fr
H04M1/00—Substation equipment, e.g. for use by subscribers
H04M1/68—Circuit arrangements for preventing eavesdropping
H04M1/70—Lock-out or secrecy arrangements in party-line systems
Landscapes
Engineering & Computer Science
(AREA)
Signal Processing
(AREA)
Telephone Set Structure
(AREA)
FR468891A1913-02-241914-02-23Dispositif pour téléphones empechant une tierce personne d'écouter la conversation entre deux postes
ExpiredFR468891A
(fr)