(19)

(11)

EP 0 214 263 A1

(12)

(43) Date of publication: 18.03.1987 Bulletin 1987/12 (21) Application number: 86901930.0 (22) Date of filing: 10.03.1986

(51) International Patent Classification (IPC):  H04B 10/ 02( . ) H04Q 11/ 00( . ) H04J 14/ 02( . ) (86) International application number: PCT/GB1986/000134 (87) International publication number: WO 1986/005649 (25.09.1986 Gazette 1986/21)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 11.03.1985 GB 19850006266 (71) Applicant: BRITISH TELECOMMUNICATIONS public limited company London EC1A 7AJ (GB)	(72) Inventors: PAYNE, David, Brian Wyckham Market Suffolk IP13 OSD (GB) STERN, Jeffrey, Richard Otley, Ipswich Suffolk IP6 9NX (GB) (74) Representative: Wolff, Eric  BRITISH TELECOM Intellectual Property Unit 13th Floor 151 Gower Street London WC1E 6BA London WC1E 6BA (GB)