Epson LQ-510 User Manual page 91

2. If the printer is on, switch it off, then hold down the FORM FEED
and LINE FEED buttons at the same time you turn on the printer.
3. Run any program that causes the printer to print (either an
application program or one in any programming language).
Your printer prints out all the codes sent to the printer, as shown
below. (In order to print the last line, you will have to take the
printer off line.)
On the left side of the printout all the codes are printed in
hexadecimal format. On the right side of the printout all
printable characters are printed, and others, such as control
codes, are represented by dots.
Using the Data Dump Mode
Using the Printer 3-25