Epson GT-6500 EN - Manual (Page 42)

5. Request condition (ESC S)
This command causes the scanner to send a data block to the
computer that contains the current values of the settings for all the
scanner’s features.
The features available are different for each scanner model. Following
is a sample of a B4-level data block sent when the scanner receives
this command.
The ESC code and command code are ASCII character data. The 1 or
2 bytes of binary data that follow are that command’s setting
(parameter) value. Two-byte data is listed with the lower byte first and
the upper byte last.
2-4 Command Usage