Epson ActionPrinter 4500 User Manual page 215

Note: Use the data dump mode to check data being sent from the
computer. In the data dump mode, data is printed in hexadecimal
format and in ASCII characters. See 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 the store where you purchased your printer or
call the Epson toll-free number (1-800-922-8911).
Troubleshooting
Printing
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