(19)

(11)

EP 1 226 734 A1

(12)

(43) Date of publication: 31.07.2002 Bulletin 2002/31 (21) Application number: 00973012.8 (22) Date of filing: 02.11.2000

(51) International Patent Classification (IPC)7: H04Q 7/38, G08B 3/10, G08B 5/22 (86) International application number: PCT/GB0004/200 (87) International publication number: WO 0133/887 (10.05.2001 Gazette 2001/19)

(84) Designated Contracting States: AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR (30) Priority: 03.11.1999 GB 9925898 (71) Applicant: CENTRAL RESEARCH LABORATORIES LIMITED Hayes,Middlesex, UB3 1HH (GB)	(72) Inventors: VERNALL, Christopher, John London NW5 2HG (GB) VERNALL, Andrew Ledbury,Herefordshire HR8 2BL (GB) SAWDON-SMITH, John London SW4 7RT (GB) (74) Representative: Sharp, Alan Cooper  QED I.P. Services Limited,Dawley Road Hayes,Middlesex UB3 1HH Hayes,Middlesex UB3 1HH (GB)