video for computer talking to another

[techidave]

I need some help finding information or a video that shows how one computer talks with another one (but not on a network).  It is for a class I am taking and the instructor is wanting something in "plain english", not geek talk.  So far when googling this I have only found for network stuff. 

Probably needing info that travels over the internet. 

Any ideas on where to look?  Maybe a youtube video?  since i have to make a video on it anyway.

thanks,
Dave