We have a def G3si running 11.2. We are having the same problem. Is your system duplicated?? We are duplicated in an MCC cabinet. When we dial in the modem connects but no login prompt appears.... does this sound familiar?? When we go out onsite the SAT is in the same state 50% of the time ( no login prompt ). If we do a spe interchange or reboot it temporarily fixes the problem but it returns. Not immediately. We have noticed it happens after it does the scheduled interchange to SPE-A. One time it took three weeks before it locked up again, the next time the same day, the next time 3 days. We have a current ticket open with Avaya if you learn anything or or figure anything out post a response and I will do the same...