How does RoundCube use imap without PHP's imap module?

[JAB Creations]

I've been scanning through RoundCube since it was able to connect to my server's imap (not sure how to put it since I'm new to messing with mail). I'm trying to figure out the *essential* part of connecting to imap on my server however I can't use the imap_open function as the module does not seem enabled on my server (without any chance of it being enabled either/bad support) but it's what I have for now.

So any way I'm simply curious about how RoundCube is able to connect to imap without the imap module? I've been scanning through code and looking stuff up on php.net without any luck however so some suggestions would be most welcomed.

[rosali]

... fsockopen ...