Okay, the cable is connected ... 'lsusb' shows that the computer can see the printer ... I click "Print Test Page" in 'Gnome-CUPS-Manager' for that printer ... I get a message saying the test page has been sent to the printer ... the status window for that printer in thr CUPS-manager shows my print job with a status of "Printing" ... and then it changes to "job stopped" and the "resume" option in the pop-up window is greyed out. Logged in as myself, this happens. Logged in a root, this still happens.
What ought-to-be-obvious (but isn't obvious from the 'man' page) detail am I most likely overlooking here? The printer is on-line as far as I can tell (it's powered up but doesn't have a separate "on-line" or "ready" LED; the LCD says "plain paper / normal / 100%" as expected, and the "error" LED is dark). At first I thought I had a bad cable, but 'lsusb' does report a device of the right brand plugged in.
The last time I managed a printer from *nix was back in the 'lpd' days, using RS232 ports and parallel ports, not CUPS nor USB.