(19)

(11)

EP 0 269 617 A1

(12)

(43) Date of publication: 08.06.1988 Bulletin 1988/23 (21) Application number: 86903940.0 (22) Date of filing: 30.05.1986

(51) International Patent Classification (IPC):  H01F 27/ 28( . ) (86) International application number: PCT/US1986/001188 (87) International publication number: WO 1987/007426 (03.12.1987 Gazette 1987/27)

(84) Designated Contracting States: DE FR GB IT NL SE (71) Applicant: AT&T Corp. New York, NY 10013-2412 (US)	(72) Inventors: PRAUGHT, Ronald, Benjamin Towaco, NJ 07082 (US) WILKOWSKI, Matthew, Anthony Bayonne, NJ 07002 (US) (74) Representative: Buckley, Christopher Simon Thirsk  AT&T (UK) Ltd. 5 Mornington Road Woodford Green Essex IG8 0TU Woodford Green Essex IG8 0TU (GB)