There is already a commented out rule in the example udev rules file
"z99_comedi.rules" to set the mode to 0660 and set the group owner to
"comedi". Add an almost identical commented out rule to set the group
owner to "iocard" as this is favoured by Debian.
# device files restricted to the "comedi" group
#KERNEL=="comedi[0-9]*", MODE="0660", GROUP="comedi"
+# device files restricted to the "iocard" group
+#KERNEL=="comedi[0-9]*", MODE="0660", GROUP="iocard"
+
LABEL="comedi_add_end"