Exhibit 16.1 [ARTHER ANDERSEN LLP LETTERHEAD] August 22, 2001 Office of the Chief Accountant Securities and Exchange Commission 450 Fifth Street, N.W. Washington, D.C. 20549 Dear Sir/Madam: We have read the first, second, third and fourth paragraphs of Item 4 included in the Form 8-K/A dated August 22, 2001 of Nx Networks, Inc. to be filed with the Securities and Exchange Commission and are in agreement with the statements contained therein. Very truly yours, /s/ ARTHUR ANDERSEN LLP Arthur Andersen LLP Copy to: Mr. John E. DuBois, Chief Executive Officer, Nx Networks, Inc.