Enterprise Systems Corporation Selected for New CS1000 Single Group, CS1000M Cabinet Installation for National Oilwell Varco

HOUSTON, TEXAS -August, 2005 - Enterprise Systems Corporation announced today that National Oilwell Varco has awarded a new system installation and upgrade contract to Enterprise Systems. The contract involves the installation of a 700 station CS1000 Single Group (Option 61C) switch at the Corporate Westchase offices utilizing IP Trunking and CallPilot Network Message Services (NMS)for centralized voice messaging. Additionally, National Oilwell's Varco will receive a CS1000M Cabinet (Option 11C) with IP Trunking back to the Corporate CS1000M Single Group (Option 61C).