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 Statement Form S-8 filed on October 21, 1999 (File No. 333-89397), Form S-3 filed on November 17, 2000 (File No. 333-48728), and Form S-8 filed on June 30, 2000 (File No. 333-40608). ARTHUR ANDERSEN LLP Dallas, Texas April 13, 2001 2