It tells you which ports are available, open, or gone. CommTool was written to solve a problem I was having with serial ports. Sometimes they didnt seem to work. Sometimes my communications programs would crash and either leave a port or a modem still running. I was stuck, wasnt sure why, and had no way to get unstuck.

If you've ever had a communications software crash on you and leave your COM port or modem locked up so you can't use it or even access it, then you know why I wrote CommTool.
When I first started programming for communications under the Windows 3.1 API (Which still works fine under Windows XP, thankyouverymuch!), I locked things up (and had to reboot) every hour. I had to stop and write CommTool so I could work without rebooting.

CommTool tells you which ports are available, open, or gone, and it lets you look at exactly how the open ports have been set up (in DETAIL). It can even modify the settings on (or close) a port while another software is using the port! It gives you incredible power over your serial ports. It does virtually everything I could think of that the Windows 3.1 API would let it do. Needs VBRUN300.DLL.

The license of this software is Freeware, you can free download and free use this protocol analyzer software.