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
Priority claimed from GB40289/58Aexternal-prioritypatent/GB857506A/en
Application filed by Bell Telephone MfgfiledCriticalBell Telephone Mfg
Application grantedgrantedCritical
Publication of BE585665RpublicationCriticalpatent/BE585665R/fr