Epson GT-6500 EN - Manual (Page 76)

Setting the scanning area
Use the ESC R, ESC H, and ESC A commands to set the scanning
area. The diagram below shows the relationship between the ESC R,
ESC H, and ESC A command parameters and the scanning area.
R
X
: Main scan resolution (in dpi)
R
Y
: Sub scan resolution (in dpi)
H
X
: Main scan zoom (in %)
H
Y
: Sub scan zoom (in %)
After setting the above values, determine the ESC A parameters based
on the following formulas:
2-38 Command Usage