EXFO FTB-500 (Window XP) - Manual (Page 395)

IEEE 488.2 and Specific Command Reference
FTB-500 387
IEEE 488.2 Required Commands
*OPC
Description The *OPC command makes synchronization
between the instrument and an external
controller possible. The *OPC command causes
the instrument to set bit 0 (Operation Complete)
in the Standard Event Status Register to the TRUE
(logic 1) state when the instrument completes all
pending operations. Detection of the Operation
Complete message can be accomplished by
continuous polling of the Standard Event Status
Register using the *ESR? common query
command. However, using a service request
eliminates the need to poll the Standard Event
Status Register thereby freeing the controller to
do other useful work.
Syntax *OPC
Parameter(s) None
See Also *OPC?
*WAI