(19)

(11)

EP 0 216 886 A1

(12)

(43) Date of publication: 08.04.1987 Bulletin 1987/15 (21) Application number: 86902442.0 (22) Date of filing: 02.04.1986

(51) International Patent Classification (IPC):  G09G 5/ 00( . ) G09G 5/ 14( . ) (86) International application number: PCT/GB1986/000190 (87) International publication number: WO 1986/005910 (09.10.1986 Gazette 1986/22)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 03.04.1985 GB 19850008668 (71) Applicant: BRITISH TELECOMMUNICATIONS public limited company London EC1A 7AJ (GB)	(72) Inventors: HUDSON, Graham, P. Pump House Suffolk (GB) REID, James, R., C. Mayfield Road Edinburgh (GB) TRICKER, Dennis, Johin Suffolk (GB) (74) Representative: Lloyd, Barry George William, et al  Intellectual Property Unit British Telecom Room 1304 151 Gower Street London WC1E 6BA London WC1E 6BA (GB)