Epson Equity 320SX PLUS - Manual (Page 185)

If you see one of the following errors, there may be a
problem with the controller or the test cable:
Error - Break detected
Error - Framing error
Error - Overrun error
Error - Parity error
Error - Time out!
Check to make sure that the test connector is securely
connected to the port. If the error persists, contact your
dealer.
Exiting System Diagnostics
To exit from the System diagnostics program, press Est. You
see the following prompt:
Do you want to
exit diag (Y/N)? N
Before you press a key, remove the Reference diskette from
drive A. If you do not have a hard disk, insert your MS-DOS
Startup diskette in the drive. Then
the program. You see this message: press Y and Enter to exit
Stand by while system is rebooting.
The computer loads MS-DOS and you see either the C : or
A :
prompt.
Performing System Diagnostics B-25