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Priority claimed from GB888800121Aexternal-prioritypatent/GB8800121D0/en
Priority claimed from GB888800221Aexternal-prioritypatent/GB8800221D0/en
Application filed by British TelecommfiledCriticalBritish Telecomm
Priority claimed from EP89300009Aexternal-prioritypatent/EP0323884B1/de
Application grantedgrantedCritical
Publication of ATE103399T1publicationCriticalpatent/ATE103399T1/de