+<p>
+The number of samples to read or write, or the size of the configuration
+structure is specified by the field <tt/n/, and the buffer for those
+samples by <tt/data/. The field <tt/subdev/ is the subdevice index
+that the instruction is sent to. The field <tt/chanspec/ specifies
+the channel, range, and analog reference (if applicable).
+
+<p>
+Instructions can be sent to drivers using <tt/comedi_do_insn()/.
+Multiple instructions can be sent to drivers in the same system
+call using <tt/comedi_do_insnlist()/.
+
+<p>Source: <tt>comedi.h</tt>