I would get a IP Phone that supports intercom, or intercom like features and get two of them. Lots of phones (I think Polycoms do this) support intercom via a

I would get a IP Phone that supports intercom, or intercom like features and get two of them. Lots of phones (I think Polycoms do this) support intercom via a auto-answer feature thats enabled for a special extension or something like that. Digging into Polycom's XML firmware might be a bit daunting for the uninitiated though, so you might want to see if Snom has something that will work for you (hell if they don't, the phones run linux!). You will probably need some kind of proxy for the phones, I like FreeSWITCH, but you can use something simpler, or Asterisk if you like it better.