EXFO FTB-500 (Window XP) - Manual (Page 335)

IEEE 488.2 and Specific Command Reference
FTB-500 325
IEEE 488.2 Required Commands
*ESR?
Description With the *ESR? query you can determine the
current contents of the Standard Event Status
Register. Reading the Standard Event Status
Register clears it. See the contents of this register
below.
Syntax *ESR?
Parameter(s) None
Response Syntax <RegisterValue>
PON URQ CME EXE DDE QYE N.U. OPC
MSB LSB
Standard Event Status
Register