National Instruments GPIB-MAC User Manual page 95

November 1985
If you passed control to some other GPIB device,control
must be passed back to you or you must send IFC to
make yourself CIC before making this call. Otherwise,
the ECIC error will be posted.
Example:
'Trigger 3 devices.
PRINT #l,"trg 2+10,4,5+7"
* frequently used function
SECTION FOUR - FUNCTIONS
84