Gday,
I have one of those belkin USB to serial adapters for use with my EQ6PRO mount and found it to be no good - reason being after about 10-15 mins of inactivity (IE the scope tracking an object) it will time out and you gotta go through resetting the mount and re-aligining again.
I bought another USB to serial adapter from jaycar and hey presto it worked all night just fine! You will also be able to get the nessesary extension cables for it there too
something about the belkin adapter is not right for astronomical use so steer clear from this one - it is also the most expensive one out there at about $79.95 i think. Jaycar version is about $39.95 so much better
Hope this helps,
Regards,
Grahame.