I can't honestly say your cable is good or bad. What I can say from my own personal experience is my old serial ALDL cable worked great with my old laptop, which had an actual 9 pin serial connector. After upgrading to a new laptop, that did not have a 9 pin serial connector, I ended up buying a USB ALDL cable from: http://aldlcable.com/products/aldlobd1u.asp I tried a couple different serial to USB adapters with my old serial ALDL cable and new laptop with limited success.

When my USB ALDL cable arrived, I plugged the new ALDL cable into my new laptop, and then I ran the driver install directly from Moates.net http://www.moates.net/usb-driver-p-215.html?cPath=78

My new laptop is Win 7.

Maybe a new USB cable is less expensive and less work than megasquirt?

dave w