Epson GT-6500 EN - Manual (Page 61)

3. Maximum scannable area
This value is expressed in units of dots (main scan
×
sub scan), based
on the maximum scannable area available when the scanner is set to
the highest available resolution and zoom is set to 100%.
Control flow
Using the ID information, you should send commands to the scanner
in the following order.
1. Obtain the scanner’s ID information by sending the ESC I command.
2. After checking the scanner function level, send commands available
at that level to make the various scanner settings.
3. Refer to the resolution and maximum scannable area information in
the ID information and set the resolution, zoom, and scanning
area.
4. Start scanning.
To scan again, repeat steps 2 through 4 above.
Command Usage 2-23