Epson GT-6500 EN - Manual (Page 213)

Error Indications
The error indications are different for the GT-6500 and the
ES-600C. Both versions are listed below.
GT-6500
Scanner errors are displayed by the digital indicator as shown
below. The READY light remains on after a Command Error.
Error name Digital indicator READY light
Command Error E-C On
Interface Error E-I Off
Fatal Error E-F (Flashes) Off
Option Error E-O Off
ES-600C
Scanner errors are displayed on the control panel by a
combination of the ERROR and READY lights as shown below.
Error name ERROR light READY light
Command Error On On
Interface Error Blinks Off
Fatal Error Blinks Blinks
Option Error Off Off
Scanner Model Technical Data B-31