The V8 Owners Forum -

Once you get a particular USB RS232 adapter working, try to remember to plug it into the same physical USB port on your laptop (assuming you have more than one). If you keep plugging it into a different port, you will find that it will come up on a different com port.

If you have a physical loopback adapter plugged in (or just short pins 2&3 together) you can use hyper terminal or putty to check that its working on the correct com port.

I also use PCMCIA UART rs232 cards for certain ECU diagnostics (especially BMW) as they don't like USB ones:

http://www.pridopia.co.uk/cardbus.html



Happy to wonder over and help out if you like.

Dunno if it helps, but on some MegaSquirts, the only way to test the entire chain is to remove the processor and link the TX and RX after the RS232 driver chip, for a loopback test. At least then you can be more certain of where the problem lies.