EXFO FTB-2 - Manual (Page 368)

IEEE 488.2 and Specific Command Reference
358 FTB-2 and FTB-2 Pro
IEEE 488.2 Required Commands
*TST?
Description The *TST? query causes an internal self-test and
places a response into the Output Queue
indicating whether or not the device completed
the self-test without any detected errors. Upon
successful completion of *TST?, the device
settings is restored to their values prior to the
*TST?.
Syntax *TST?
Parameter(s) None
Response Syntax
Response(s) Result:
The response data syntax for is
defined as a
element.
The value ranges from -32767 through
+32767.
A with a value of zero indicates that
the self-test has been completed without errors
detected. A with a value not equal to
zero indicates that the self-test was not
completed or was completed with errors
detected.
Example(s) *TST? returns 0
(self-test was completed with success)