(19)

(11)

EP 0 409 841 A1

(12)

(43) Date of publication: 30.01.1991 Bulletin 1991/05 (21) Application number: 89902390.0 (22) Date of filing: 15.02.1989

(51) International Patent Classification (IPC):  G06F 13/ 14( . ) H04L 12/ 00( . ) G06F 15/ 177( . ) H04L 12/ 50( . ) (86) International application number: PCT/FI1989/000027 (87) International publication number: WO 1989/007797 (24.08.1989 Gazette 1989/20)

(84) Designated Contracting States: BE CH DE FR GB IT LI NL SE (30) Priority: 17.02.1988 FI 19880000754 (71) Applicant: VALTION TEKNILLINEN TUTKIMUSKESKUS SF-02150 Espoo 15 (FI)	(72) Inventor: LEPPÄLÄ, Kari, Paavo, Antero SF-90530 Oulu (FI) (74) Representative: Grünecker, Kinkeldey, Stockmair & Schwanhäusser Anwaltssozietät  Maximilianstrasse 58 D-80538 München D-80538 München (DE)