Original config: ArchiCAD 7.0 v3; Mac dual 1 gig G4 OS 10.2; Designjet 220, Jetdirect EX J2382B.....could not assign J2382B an IP address; telnet did not work, and box did not assign itself an address. So, I picked up a JetDirect EX 300 from ebay, $58.75, and lo and behold, it assigned itself an IP address, and therefore it was addressable by telnet. Start up Terminal (unix command line utility), give command "telnet (ip address of jetdirect)", which starts up telnet and hooks up to jetdirect. Give command "/" which returns the status of the jetdirect, including its ip address. Give command "ip: (ip address you want to give it)". Then "quit".
Then go to Plot setup dialog, configure it to address the IP address you input to the jetdirect, use port number 9100, and you can plot directly from Archicad.
The plot quality so far seems poor however....I got much better results in the old days with the PowerPlot driver under Mac OS 7.5.
Question is, which IP address to be assigning. I believe that the G$ and jetdirect addresses need to have the first same 2 numbers, i.e., numbers like 169.254.xxx.xxx, where the 169 and the 254 have to be on both machines; and the others must have at least some difference. The G4 is set to assign itself its own IP address, and could theoretically accidentally assign itself the same address as the jetdirect box, in which case plotting would not work......something to watch.
So, I'm sure some more knowledgeable people out there could correct this, it's a bit like the blind leading, but it's working now!!