RxTx measures the data transfer bandwidth between your computer and multiple servers. It works with Dial-Up, Cable or DSL connections.
Bandwidth is measured by downloading one or more HTTP files and averaging the received data rates. You can specify a number of Internet addresses (or files) as they appear on your browser Address bar. The download speed is lower for binary files than for text (ASCII) files so you should choose both binary (.jpg, .gif, .exe, .zip) and text (.html, .asp, .txt) files for test.