Better late than never? Reproduced here because I had a hard time finding this link
socat PTY,link=COM8 PTY,link=COM9
This creates COM8 and COM9 as appropriate symbolic links in the current working directory; now you can open two new terminal windows in the same directory and type
and the two terminals will now be communicating. Notice that unlike pty/tty, you don't have to worry about starting up the master first anymore! (COM8 and COM9 both point to "slave" /dev/pts entities). Also, dare I point out that once socat has been called, this is just as user-friendly as com0com in Windows??