Exhibit 23.1 CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the incorporation of our report dated January 28, 2000 included in this Form 10-K, into the Company's previously filed Registration Statement File Nos. 333-01410, 333-35283, 333-83925 and 333-88913. /s/ ARTHUR ANDERSEN LLP Philadelphia, Pa. February 23, 2000