(19)

(11)

EP 0 437 482 A1

(12)

(43) Date of publication: 24.07.1991 Bulletin 1991/30 (21) Application number: 89911234.0 (22) Date of filing: 05.10.1989

(51) International Patent Classification (IPC):  H04Q 1/ 14( . ) (86) International application number: PCT/AU1989/000431 (87) International publication number: WO 1990/004313 (19.04.1990 Gazette 1990/09)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 05.10.1988 AU 19880000781 (71) Applicant: AUSTRALIAN AND OVERSEAS TELECOMMUNICATIONS CORPORATION Melbourne Victoria (AU)	(72) Inventors: LONGLAND, David, George The Gap, QLD 4061 (AU) LEWIN, John, Norman Albany Creek, QLD 4035 (AU) RADKE, Keith, Frederick Mudjimba, QLD 4564 (AU) DUNCAN, Kenneth, David Greenslopes, QLD 4120 (AU) (74) Representative: Hale, Peter  Kilburn & Strode 30 John Street London WC1N 2DD London WC1N 2DD (GB)