1 EXHIBIT 23.1 CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the incorporation of our report included in this Form 10-K into the Company's previously filed Registration Statements (File No. 333-53083, File No. 333-60135 and File No. 333-80931). /s/ Arthur Andersen LLP Baltimore, Maryland, March 30, 2000