I have a customer whose has a 0x32 and 4.1 software. They had been running a AT@T PRI circuit for years, and the had no issues. The customer changes to a different carrier(XO), and now every four days or so the PRI drops, they unplug the Norstar, plug it back in and they are good to go for the next four days. We have changed the KSU(but put the old software back in), the combo card, the DTI card and ran a new cable to the demarc. The clocking is set to primary. The norstar is running B8zs, and ESF, which matches the circuit parameters, there is no CSU, so the internal Norstar one is turned on, we have put a T1 watcher on it and the circuit is error free...until it drops. Any ideas?