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.)
AT&T Corp
Original Assignee
American Telephone and Telegraph Co Inc
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 US06/265,195external-prioritypatent/US4439759A/en
Application filed by American Telephone and Telegraph Co IncfiledCriticalAmerican Telephone and Telegraph Co Inc
Priority to CA000516984ApriorityCriticalpatent/CA1229935A/fr
Application grantedgrantedCritical
Publication of CA1229935ApublicationCriticalpatent/CA1229935A/fr