Not sure you will be able to just connect the Plus to a PC. Check out this link for some cross platform networking tips.

http://www.vintagemacworld.com/netmain.html

Now, I have been able to use Mac OS X Terminal to send files over a serial connection, so theoretically this may work just as well with a modern PC. I'm using MacTerminal on my compact Mac, but ZTerm may work just as well.