(19)

(11)

EP 0 815 695 A1

(12)

(43) Date of publication: 07.01.1998 Bulletin 1998/02 (21) Application number: 96909632.0 (22) Date of filing: 07.03.1996

(51) International Patent Classification (IPC):  G01D 4/ 00( . ) G08G 1/ 123( . ) H04W 8/ 12( . ) G07C 5/ 00( . ) H04B 7/ 185( . ) (86) International application number: PCT/US1996/003250 (87) International publication number: WO 1996/029831 (26.09.1996 Gazette 1996/43)

(84) Designated Contracting States: AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 17.03.1995 US 19950406022 21.04.1995 US 19950426743 (71) Applicant: HIGHWAYMASTER COMMUNICATIONS, INC. Dallas, Texas 75248 (US)	(72) Inventors: KENNEDY, William, C., III Dallas, TX 75231 (US) RUSSELL, Thomas, D. Plano, TX 75075 (US) WESTERLAGE, Kenneth, R. Fort Worth, TX 76118 (US) (74) Representative: Harris, Ian Richard  D. Young & Co., 21 New Fetter Lane London EC4A 1DA London EC4A 1DA (GB)