National Instruments GPIB-PC - Manual (Page 213)

Section Five IBIC
©National Instruments Corp. 5-25 GPIB-PC User Manual
GPIB0:
[4188] (timo cmpl lok cic atn tacs )
ibwait (TIMO SRQI)
Set up the device for a serial poll. The ? and _ represent the unlisten
(UNL) and untalk (UNT) characters, respectively, and reset the address.
The hex value 18 represents the serial poll enable function, while the
A
represents the device's talk address.
Example:
GPIB: ibcmd "?_\x18A"
Read the status byte. The status byte returned may vary depending on
the device used.
Example:
GPIB0:
[01E4] (cmpl lok rem cic atn lacs)
count: 1
50P
ibrd 1
Complete the serial poll by sending the serial poll disable message
(SPD).