(19)

(11)

EP 0 228 455 A1

(12)

(43) Date of publication: 15.07.1987 Bulletin 1987/29 (21) Application number: 86904577.0 (22) Date of filing: 26.06.1986

(51) International Patent Classification (IPC):  H04K 1/ 06( . ) H04L 9/ 08( . ) (86) International application number: PCT/US1986/001364 (87) International publication number: WO 1987/000377 (15.01.1987 Gazette 1987/01)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 27.06.1985 US 19850749939 (71) Applicant: CODART COMMUNICATIONS, INC. Santa Rosa, CA 95401 (US)	(72) Inventors: MAISEL, Douglas, Andrew Berkeley, CA 94704 (US) McREYNOLDS, John, Frederick Berkeley, CA 94708 (US) WEISMAN, Joe San Francisco, CA 94114 (US) CARLSON, Charles, Edward Berkeley, CA 94708 (US) (74) Representative: Cross, Rupert Edward Blount  BOULT, WADE & TENNANT 27 Furnival Street London EC4A 1PQ London EC4A 1PQ (GB)