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.)
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Application filed by American Telephone & TelegraphfiledCriticalAmerican Telephone & Telegraph
Priority claimed from EP86903815Aexternal-prioritypatent/EP0225374B1/de
Application grantedgrantedCritical
Publication of ATE56104T1publicationCriticalpatent/ATE56104T1/de