(19)

(11)

EP 0 555 297 A1

(12)

(43) Date of publication: 18.08.1993 Bulletin 1993/33 (21) Application number: 91918826.0 (22) Date of filing: 28.10.1991

(51) International Patent Classification (IPC):  H04M 3/ 51( . ) H04M 3/ 493( . ) H04M 3/ 62( . ) (86) International application number: PCT/GB1991/001883 (87) International publication number: WO 1992/008197 (14.05.1992 Gazette 1992/11)

(84) Designated Contracting States: BE DE FR GB IT LU NL SE (30) Priority: 29.10.1990 GB 19900023506 (71) Applicant: PSYCHOMETRIC RESEARCH & DEVELOPMENT LTD. St. Albans, Herts. AL1 3HT (GB)	(72) Inventors: BLINKHORN, Stephen Frederick St. Albans, Herts. AL1 3TX (GB) SIMMONS, Craig St. Albans, Herts. AL1 3AQ (GB) (74) Representative: Beresford, Keith Denis Lewis, et al  BERESFORD & Co. 2-5 Warwick Court High Holborn London WC1R 5DJ London WC1R 5DJ (GB)