In other words, I can call the modem, then dial a PIN ("12345") and it'll authenticate me and connect. :D I could play my iPod through the modem's mic input and hear the music through the phone handset! :D I stayed at work until 7:30 and got to make it play tones to the user (e.g. "ready" tone so the user knows when to dial their PIN, an "error" tone if they get it wrong and a dinky little tune (CDE) when they get it right).
Going back into work again tomorrow. Yes, Saturday. Yes, I did work 11