Exhibit 21 Applied Cellular Technology, Inc. List of Subsidiary Companies Company Name Country or State of Incorporation ACT Acquisition Corp. Delaware ACT Automotive Group, Inc. Delaware ACT Financial Corporation Delaware ACT Communications, Inc. Delaware Advanced Telecomm Holdings, Inc. Delaware Advanced Telecomm of Pittsburgh, a Pennsylvania Business Trust Pennsylvania Advanced Telecomm of Butler, Inc. Pennsylvania Advanced Telecomm of Washington D.C., Inc. Pennsylvania Advanced Telecomm of Maryland, Inc. Maryland Advanced Telecomm of Nevada, Inc. Nevada Advanced Telecommunications, Inc. Illinois Alacrity Systems, Inc. New Jersey Applied Cellular Technology International, Lt United Kingdom Applied Cellular Technology of Missouri, Inc Missouri Atlantic Systems, Inc. New Jersey Burling Instruments, Inc. New Jersey C.T. Specialists, Inc. California Canadian Network Services, Inc. Delaware City Dial Network Services, Ltd. Ontario, Canada Delaware Tele-Resources, Inc. Ontario, Canada Cra-Tek Company California Cybertech Station, Inc. Pennsylvania Elite Computer Services, Inc. New Jersey Hopper Manufacturing Co., Inc. California MVAK Technologies, Inc. New Jersey Norcom Resources, Inc. Minnesota Pizarro Re-Marketing, Inc. Texas PPL, Ltd. New York Signal Processors, Ltd. United Kingdom STC Netcom, Inc. California Universal Commodities Corp. New Jersey US Electrical Products Corp. New Jersey 10-K Page 70