Printronix P9000 Series - Manual (Page 185)

8-7 Routine Service & Diagnostics
6. Send the data from the host; the hex dump will print.
7. Press ON LINE again to stop the hex dump. The display will read OFFLINE HEX
DUMP.
8. Press CLEAR to return printer to OFFLINE READY.
9. Close printer cover and place the printer on line.
NOTE: Any data remaining in the buffer will be printed before the hex code printout
starts.