Epson LQ-850 User Manual page 118

Troubleshooting
3. To turn off the data dump mode, press the ON LINE button to
stop the printing and set the printer off line, then turn off the
printer. (It can also be cancelled by sending an INIT signal from
the computer .)
The data dump shown in Step 2 was made while writing this
section. By comparing the characters printed in the right column
with the printout of hex codes, you can check what codes are being
sent to the printer. If characters are printable, they appear as their
true ASCII characters. Non-printable codes, such as control codes,
are represented by dots.
As an example of how to interpret a data dump printout, look at
the first three hex codes on the second line of the printout sample
(20 20 54). Each hex code (20) represents a space; while the hex
code (54) represents the letter T. Check the second line of the right
column and you will find the letter T preceded by two spaces.
The chart below interprets the first seven non-printable codes:
Hex codes Command
6-6
Function
Initialize printer
Select USA character set
Select Epson Extended Graphics
Printable code expansion
Cancel condensed mode
Select pica
Cancel proportional