Epson GT-6500 EN - Manual (Page 66)

Status byte
This byte indicates the color of the image data or the state of the
scanner. Each bit in the Status byte has a different meaning, as shown
in the following diagram. Currently, bits 0, 1, and 6 are reserved (not
used).
Error flag (bit 7)
This flag is set to ‘‘1’’ when an error other than a command error
occurs. In this case, no data follows, so the byte counter is set to 0
(00
H
, 00
H
).
If a system error occurs, the scanner accepts only the ESC F and ESC
f commands. These two commands are used to determine if a system
error has occurred.
Area end flag (bit 5)
This flag is set to ‘‘1’’ when the data block is the final block of
scanned data in the scanning area. Do not send an ACK code to the
scanner after receiving the final data block (when this flag is set to 1).
Option flag (bit 4)
This flag is set to ‘‘1’’ when an option is installed.
2-28 Command Usage