What is the difference between the Xbox 360 USB controllers (one for Windows and one for Xbox 360)?

Question

For $39.99 retail I can get the wired USB controller for Xbox 360, which incidentally works on Windows PCs as well. For another $5, I can get the Xbox 360 Controller for Windows. Does anyone know what the difference between the two is? Is it just the software that comes on the CD with the Windows version of the controller (which can be downloaded for free from Microsoft)? Or is there something else I'm missing?

Here are the two product pages from Best Buy. They didn't shed any light.

http://www.bestbuy.com/site/olspage.jsp?skuId=7477349&type=product&id=1125465741642
http://www.bestbuy.com/site/olspage.jsp?skuId=7457619&type=product&id=1126591945634

Answer 1

The controller for windows is basically the same as the xbox 360 except for some minor difference. It has a Universal Asynchronous Receiver Transmitter (UART) for game pad accessory receptacle or plug-in module.