1 EXHIBIT 23.1 CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the incorporation of our reports included in this Form 10-K, into the Company's previously filed registration statements, Reg. Nos. 333-96341, 333-31342, 333-85791, 333-53667, 333-28147, 333-27009 and 333-03703. /s/ ARTHUR ANDERSEN LLP March 21, 2000 Dallas, Texas