Epson 4500 - Manual (Page 107)

Using the Data Dump Mode
4. To turn off the data dump mode after you have taken the printer off
line, turn off the printer.
By comparing the characters printed in the text field on the right side of
the data dump printout (see step 3) with the printout of hex codes, you
can check which codes are being sent to the printer.
To interpret the data dump printout, examine the first three hex codes
on the second line of the printout sample (20 20 54). Each hex code 20
represents a space; hex code 54 represents the letter T. Check the second
line of the text field on the right side of the printout and you will find
the letter T preceded by two spaces.
The chart below interprets the first eight codes.
Hex codes Command Function
1B40 ESC Initialize printer
1B5200 ESC R 0 Select USA character set
1B7401 ESC t1 Select Epson Extended Graphics set
3-28 Using the Printer