Epson GT-6500 EN - Manual (Page 73)

Single data blocks
Use when you expect single data blocks in response to the ESC I
(Request ID) command, the ESC S (Request condition) command, the
ESC F (Request status) command, and the ESC f (Request extended
status) command.
Scanning Area
The following commands affect the scanning area: the ESC R (Set
resolution) command, the ESC H (Set zoom) command, and the ESC
A (Set scanning area) command. The parameter values in the ID
information are used in these commands. The relationship between
these commands and the scanning area is explained below.
Command Usage 2-35