I am trying to use my 9 pin serial port to connect my automotive ECU to my computer (megasquirt controller). I've done this before with Ubuntu 10.04 but now that I've just upgraded to 12.04 it simply will not connect. I didn't have any issue before. Now I simply cannot open this port.
chmod I get this:
~$ chmod o+rw /dev/ttyS0 chmod: changing permissions of `/dev/ttyS0': Operation not permitted