A serial adapter may work ok but its hit and miss with the Combros and laptops specifically.

I have just made up another batch of USB-Chrony/Combro cables. They are not much more than a Combro cable and serial adapter with shipping taken into account and they definately work every time as they are designed for USB.

Whichever way you go, take a peek at the software in my sig, usefull even in demo mode.

Cheers
Stot