Introduction - If you have any usage issues, please Google them yourself
This requires Visual Studio 2010 to compile, which can be obtained free via C# Express. It is just a simple little application with basic support for text or binary (hex) modes to send and receive data. A nice feature or two is auto-detection of installed COM ports that update at runtime if you plugin or remove USB-to-Serial adapters, also you can change the DTR and RTS levels and monitor the CTS, DSR, and CD lines.