G rex question

What is the G-Rex ? Is that a kind of a breakout board to fit between a PC
and stepper or servo drives?..
.
I understand it is new and not entirely ready to be widely distributed to
every hamfisted newbie who is slapping a cnc together?
.
My situation is that I am getting ready to upgrade an old cnc lathe to run
on Mach3/ PC and that lathe has/requires more inputs/outputs than can be
handled with a single 'Bob Campbell's breakout board.... So I am wondering
how I should proceed...One option might be to run a second breakout board
from a second printer port - but dont know how to do that..But that may be
my only/best option - unless G-rex---------?
.
Steven