You don't
need a USB to RS232 convertor, but you can use one.
I bought one of these
http://apple.clickandbuild.com/cnb/s...dCategoryID=47 as linked from the EQMod website, and attached an RJ45 plug on the end. The wiring configuration is also on the EQMod website.
I believe there is an online store down south somewhere in Australia now that sells them too.