custom Dreamcast parallel port

sorry for the mass mail but my google searching has netted me nothing :(

i've been looking at all the custom hardware hacks people have done with their 
dreamcasts and what many of them do is use the parallel port, as can be seen 
in the following pic:
http://home.b00.itscom.net/ikehara/dc/pictures/p0206n002.jpeg

i havent been able to find any directions on how to build this but since many 
places mention the modem, i imagine they used the connector off the modem 
board and just soldered the wires into that ... does anyone out there know of 
a place with some good directions on how to build this myself ?  i'd rather 
work off something that someone has done before (and thus proven to work) 
than just break it myself and have to buy another one :)
-mike