EXHIBIT 17.1 January 5, 2006 Via Facsimile & First Class Mail 949 753-7499 Network Installation Corporation 15235 Alton Parkway, Suite 200 Irvine, CA 92618 Attn: Jeff Hultman Re: Board of Directors Network Installation Corporation To Jeff Hultman and the Board of Directors: Please accept my resignation from the Board of Directors of Network Installation Corporation effective January 5, 2006. I wish you success in the future. Please do not hesitate to contact me if I can be of further assistance. Thank you. Very truly yours, /s/ William G. Sullivan WILLIAM G. SULLIVAN