Data Dump Mode - Epson LQ-2550 User Manual

Data Dump Mode

The printer has a feature to find the cause of communication
problems between the printer and application programs. In data
dump mode a printout of the codes reaching the printer is
produced.
1. To enter the data dump mode, hold down the FORM FEED and LINE
FEED buttons at the same time while you turn on the printer.
2. Next, run either an application program or one you have written in
any programming language. Your printer prints all the codes sent to
the printer in hexadecimal format as shown below:
3. To turn off the data dump mode, press the ON LINE button to take the
printer off line, and then turn off the printer. (The data dump mode
can also be cancelled by sending an INIT signal from the computer.)
Look at the data dump shown in Step 2. By comparing the characters
printed in the right column with the printout of the hexadecimal codes,
you can check what codes are being sent to the printer. If characters are
printable, they appear as their true ASCII characters. Nonprintable
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 20 represents a space, while hex 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 part of the first line of codes:
6-6
01
ESC @
ESC RO
ESC tl
78 61
Initialize printer
Select USA character set
Select Epson Extended Graphics
it easy io
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