My experience with printing out the HPGL/2 Configuration Page was that it returned a bogus IP address. The easiest thing to do was to set a new address. To reset the JetDirect box, do the following:
1. Disconnect serial cable to CPU.
2. Disconnect power cord to JD box.
3. Plug power cord back into box while holding down "Test" button.
4. Let go after "Status" light flashes.
Then you need to set new TCP/IP. I used Laserwriter Utility 3.4 (only works in Classic). There might be something newer/better that works in OS X by now--this was a year or more ago.
1. Select "Jetdirect EX". "HP Peripheral" should show in the list of available printers.
2. Highlight and choose "Info" button.
3. Choose new IP address (Ping first to be sure address is not already in use)
Dave JochumJ o c h u m A R C H I T E C T S http://www.jochumarchitects.comMBP 16" (M1 Max) 64 GB•OS 13.2.1•AC 26 Silicon (latest build)