(19)

(11)

EP 0 909 492 A2

(12)

(43) Date of publication: 21.04.1999 Bulletin 1999/16 (21) Application number: 97928551.0 (22) Date of filing: 27.06.1997

(51) International Patent Classification (IPC):  H04L 12/ 403( . ) (86) International application number: PCT/NZ1997/000086 (87) International publication number: WO 1998/000925 (08.01.1998 Gazette 1998/01)

(84) Designated Contracting States: AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 28.06.1996 NZ 19960286908 (71) Applicant: Digi-Tech Research and Development Limited Wellington (NZ)	(72) Inventors: ATKINS, Peter, David Wellington (NZ) LITTEK, Arnim Holger Wellington (NZ) WORTHINGTON, James, Stephen Lower Hutt (NZ) (74) Representative: Harland, Linda Jane, et al  c/o Reddie & Grose 16 Theobalds Road London WC1X 8PL London WC1X 8PL (GB)