Omron FQ2-S/CH Series User Manual page 285

ECHO or EEC
Executes Echo-back (Loop-back).
This command returns as is any character string sent by an external device. Only single-byte alphanumerics
can be used.
<Command format>
E C H O
Space (0x20)
or
E E C
Space (0x20)
<Response format>
When processing is performed normally
When processing is not performed normally
<Parameters explanation>
Arbitrary character string
FQ2-S/CH User's Manual
for Communications Settings
C
R
Arbitrary character string (256 characters max.)
C
R
Arbitrary character string (256 characters max.)
Sets the character string returned as is. The response is the character string set here as
is.
283
Command Control