I have been dealing with several customers experiencing the same issue. Norstar forwards incoming calls to various cell phones. If the cell phone is a T-Mobile the call will fail with all circuits are busy or call can’t be completed at this time. The lec says the norstar isn’t sending a ISDN_progress and therefore the lec's switch disconnects the call because it hasn’t completed in time. It only does this on norstars and to T-Mobile cell phones.
This is a NI2 PRI over VOIP, it plugs into a Cisco iad 2432.
This is a NI2 PRI over VOIP, it plugs into a Cisco iad 2432.