EXFO FTB-500 (Window XP) - Manual (Page 405)

IEEE 488.2 and Specific Command Reference
FTB-500 397
IEEE 488.2 Required Commands
*WAI
Description The *WAI command shall prevent the device
from executing any further commands or queries
until the no-operation-pending flag becomes
TRUE.
Syntax *WAI
Parameter(s) None
Example(s) *WAI
See Also *OPC
*OPC?