The rules file is called 50-ioio.rules and the the text is:
ACTION=="add", SUBSYSTEM=="tty", SUBSYSTEMS=="usb", SYMLINK+="IOIO%n", MODE="666"
I copied this file to the udev rules directory using:
sudo cp 50-ioio.rules /etc/udev/rules.d
I then restarted udev using:
sudo restart udev
However when I connect the IOIO board via a USB cable and look for the serial port with
ls /dev/IOIO*
It is not being created? I cant find any errors in syslog or anything in dmesg or lsusb - I suspect the udev string is wrong but it is in the documentation for the device?
I restarted the whole box and it got discovered, its not the real answer but at least I can progress