Epson LX-810 User Manual page 213

Printing
Note: You can also use the data dump mode to find the cause
of communication problems between the printer and your
application programs. In data dump mode, an exact printout of
the codes reaching the printer is produced. See the section on
the data dump mode in Chapter 3.
If the printer still does not print, try the self test described in
Chapter 1. If the self test works properly, the printer is all right,
and the problem probably lies in the computer, the software or the
cable. If the self test does not work, contact your Epson dealer.
Troubleshooting 7-13