I just tried four different USB-to-serial (DB9) adapters in order to get XP in my laptop to communicate with a MoTeC M4. The two that worked well were:

• - TrippLite Serial to USB Adapter (Model U209-000-R)
  http://www.tripplite.com/EN/products...xtModelID=3914
• - High-Speed USB Serial Adapter (Model USA-19HS)
  http://www.keyspan.com/products/usa19hs/

I've heard favorable feedback about a "Radio Shack" adapter but have not had direct experience.

 

i used a no brand cheap one from best buy and worked fine with my haltech and wideband kit. i think i payed 40 bucks for it. are you configurating the ports right? did you set up the software?