This was posted as a question to the FAQ section of the PLUG web site:

"I want to connect to the internet through COX high speed internet service
with my Mandrake 8.2 distrobution. I tried to order online but the only
options are MS and Mac. The question. Shouldn\'t I be able to connect without
one of those OS\'s? What about if I use a router? Thanks,"

Obviously, connection to Cox without MS or Mac is possible.  Using a router is
fine or direct connection to the cable modem works to.  However, I don't know
how to answer the what to order part.  

I assume a Linux user could order either MS or Mac and it would not matter
because that just specifies what sort of software they will provide to you. 
Neither of which will be used because Linux provides everything needed.  I
don't have Cox service so I am guessing here.  Is this correct?

Alan