(19)

(11)

EP 0 158 674 A1

(12)

(43) Date of publication: 23.10.1985 Bulletin 1985/43 (21) Application number: 84903787.0 (22) Date of filing: 10.10.1984

(51) International Patent Classification (IPC):  G04B 47/ 06( . ) G04G 9/ 00( . ) (86) International application number: PCT/US1984/001612 (87) International publication number: WO 1985/001805 (25.04.1985 Gazette 1985/10)

(84) Designated Contracting States: AT BE CH DE FR GB LI LU NL SE (30) Priority: 11.10.1983 US 19830540685 (71) Applicants: ISMAIL, Nassar Ahmed Cambridge, MA 02142 (US) ABDEL-RAHMAN, Mahmoud F. West Grove, PA 19390 (US) AHMED, Moustafa Elshafei Worcester, MA 01602 (US)	(72) Inventors: ISMAIL, Nassar Ahmed Cambridge, MA 02142 (US) ABDEL-RAHMAN, Mahmoud F. West Grove, PA 19390 (US) AHMED, Moustafa Elshafei Worcester, MA 01602 (US)