These units were specifically made for the VoIP service AT&T Callvantage. If you're lucky enough to get the runtime module and the prom update, you'll have yourself a really nice, free, voip box. This update brings the unit from 1120M to 1120S. Still can't use the other phone jack; there's no relays, or code to support it.
Calling AT&T for the password is also futile. Callvantage is no longer in business, but their VoIP boxes live on. Like any crumbling empire, the emperor spits his last breath of death at thee. Unlocking these boxes so their customers, and the rest of the public, could use them would not dilute their earnings, nor would it take away from their revenue. In my opinion, the only reason AT&T offered this voip service was to keep from looking worse then they already do, and continue to hold onto their rights on this box for no other reason but spike and malice.