National Instruments NI-488.2M Software Reference Manual page 140

Appendix A Status Word Conditions
RQS (dev)
RQS appears in the status word only after a device-level call. RQS indicates that
one or more automatic serial poll response bytes are waiting in the device's serial
poll response queue. Automatic serial poll responses are not stored in the
response queue unless they have bit 6 set.
An automatic serial poll occurs as a result of a call to ibwait, or it occurs
automatically if automatic serial polling is enabled. If the serial poll response
queue is not empty, ibrsp returns the oldest byte stored in the queue. To
empty the response queue, call ibrsp repeatedly until RQS is no longer set in
the device's status word.
CMPL (dev, brd)
CMPL indicates the condition of I/O operations. It is set whenever an I/O
operation is complete. CMPL is cleared while the I/O operation is in progress.
LOK (brd)
LOK indicates whether the board is in a lockout state. While LOK is set, the
EnableLocal routine or ibloc function is inoperative for that board. LOK
is set whenever the GPIB board detects the Local Lockout (LLO) message has
been sent either by the GPIB board or by another Controller. LOK is cleared
when the System Controller unasserts the Remote Enable (REN) GPIB line.
© National Instruments Corp. A-3 NI-488.2M SRM for OS/2