you can buy a firewire card.
JV3 has a parallel and firewire port. You can use a print server (small box with parallel on one end, ethernet on the other) to accomplish what you are wanting, basically running the ethernet cable up to 300' from the computer. We tried this however and found that the printer was not getting data fast enough. On some jobs that were very detailed it would pause the head and wait for data, not good! We ended up using firewire.