(19)

(11)

EP 0 922 258 A1

(12)

(43) Date of publication: 16.06.1999 Bulletin 1999/24 (21) Application number: 97907643.0 (22) Date of filing: 18.02.1997

(51) International Patent Classification (IPC):  G06F 12/ 00( . ) G06F 17/ 30( . ) (86) International application number: PCT/US1997/002407 (87) International publication number: WO 1997/031319 (28.08.1997 Gazette 1997/37)

(84) Designated Contracting States: GB (30) Priority: 23.02.1996 US 19960012151P 07.02.1997 US 19970797756 (71) Applicant: AT&T Corp. New York, NY 10013-2412 (US)	(72) Inventors: BALL, Thomas, J. Naperville, IL 60540 (US) CHEN, Yih-Farn, Robin Bridgewater, NJ 08807 (US) DOUGLIS, Frederick Somerset, NJ 08873 (US) KOUTSOFIOS, Elefterios Chatham, NJ 07928 (US) (74) Representative: Asquith, Julian Peter, et al  Marks & Clerk, Nash Court, Oxford Business Park South Oxfordshire OX4 2RU Oxfordshire OX4 2RU (GB)