National Instruments GPIB-PC - Manual (Page 110)

Section Four A BASICA/QuickBASIC GPIB-PC Function Calls
©National Instruments Corp. 4A-35 GPIB-PC User Manual
Board Example:
1. Turn the ATN line off with the IBGTS function after
unaddressing all Listeners with the Unlisten (UNL or ASCII ?)
command, addressing a Talker at &H46 (ASCII F) and
addressing a Listener at &H31 (ASCII 1) to allow the Talker to
send data messages.
100 CMD$ = "?F1" ' UNL MTA1 MLA2
110 CALL IBCMD (BRD0%,CMD$)
120 V% = 1
' Listen in continuous mode.
130 CALL IBGTS (BRD0%,V%)