The link is established in Windows using the Mono implementation of System.IO.Ports.
For Mac/OSX users, I've made an implementation that uses SerialProxy because direct serial connection doesn't work on the mac. The problem is, though, that the SerialProxy implementation doesn't seem to work either.
Check out the Mac_OSX_problems Wiki for more documentation about this.
To sum it up, we have 2 kind of connections:
To get the connections working, Use one of these guides:
Project established by: Tiuri de Jong.