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Priority claimed from GB878721603Aexternal-prioritypatent/GB8721603D0/en
Priority claimed from GB888804552Aexternal-prioritypatent/GB8804552D0/en
Application filed by British TelecommfiledCriticalBritish Telecomm
Priority claimed from EP88308382Aexternal-prioritypatent/EP0308150B1/de
Application grantedgrantedCritical
Publication of ATE91364T1publicationCriticalpatent/ATE91364T1/de