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Priority claimed from GB848420013Aexternal-prioritypatent/GB8420013D0/en
Priority claimed from GB848424860Aexternal-prioritypatent/GB8424860D0/en
Application filed by British TelecommfiledCriticalBritish Telecomm
Priority claimed from EP85305572Aexternal-prioritypatent/EP0174729B2/de
Application grantedgrantedCritical
Publication of ATE39396T1publicationCriticalpatent/ATE39396T1/de