ModemTest is an easy to use Windows-based application that allows users to test their dial up modem. ModemTest performs low level testing that is independent of your Internet Service Provider (ISP) and the TCP/IP settings on the computer. It allows the modem to be tested in addition to the phone line the modem is connected to. ModemTest provides a method for system integrators and computer repair centers to test both internal and external modems. By a process of elimination, home users can also use the ModemTest to help isolate Internet connection problems to a faulty modem, or phone line or their ISP service. ModemTest logs any data corruption and incorporates a modem speed test which reports the initial connection speed and the actual throughput. Two different test methods are provided. The first test method uses two telephone lines and two modems in a master/ slave configuration. The master dials the phone number of the slave modem and after a successful connection, data packets.