(19)

(11)

EP 1 374 470 A1

(12)

(43) Date of publication: 02.01.2004 Bulletin 2004/01 (21) Application number: 02709843.3 (22) Date of filing: 14.03.2002

(51) International Patent Classification (IPC)7: H04L 7/00 (86) International application number: PCT/US2002/008062 (87) International publication number: WO 2002/082713 (17.10.2002 Gazette 2002/42)

(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: 05.04.2001 US 827513 29.06.2001 US 895493 (71) Applicant: Schweitzer Engineering Laboratories, Inc. Pullmann, WA 99163 (US)	(72) Inventors: LEE, Tony, J. Pullman, WA 99163 (US) HAWBAKER, Jeffrey, L. Pullman, WA 99163 (US) (74) Representative: Faulkner, Thomas John et al fJ Cleveland,40-43 Chancery Lane London WC2A 1JQ London WC2A 1JQ (GB)