(19)

(11)

EP 1 234 291 A1

(12)

(43) Date of publication: 28.08.2002 Bulletin 2002/35 (21) Application number: 00977701.2 (22) Date of filing: 23.11.2000

(51) International Patent Classification (IPC)7: G08G 1/017 (86) International application number: PCT/GB0004/459 (87) International publication number: WO 0103/9153 (31.05.2001 Gazette 2001/22)

(84) Designated Contracting States: AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR Designated Extension States: AL LT LV MK RO SI (30) Priority: 24.11.1999 GB 9927623 (71) Applicant: ADT Services AG 8201 Schaffhausen (CH)	(72) Inventor: SMITH, David Raymond Cambridge CB4 5LD (GB) (74) Representative: Pratt, David Martin et al Withers & Rogers,Goldings House,2 Hays Lane London SE1 2HW London SE1 2HW (GB)