Ek's box sends data as text (and it supports couple of formats).
Bartel's scope.exe deals with this directly, without special driver.
have a look here:
http://eksfiles.net/digital-setting-circles/
I wouldn't try to reinvent the wheel here.. really no need.
Ek's box can't be simpler in terms of h/w.. and firmware is available as well (freeware.. even as a source code.. but you have to ask David for this first)