No alarms in the 'Network Event Log'? Also, pulling cable from the Smart Jack resets your card? This is indeed strange. What s/w level is your Norstar running? There were some s/w levels that had b-channel lockup issues. When it stops working, look at the d-channel and see if that is active and if it is, what is the state of the b-channels? Telco is only going to look at DS1 errors until you move to the DS0/data group. If they are having a d-channel issue, it won't show up as a DS1 error when they test. I would look first at the s/w level of the Norstar first. Also, look at your routing and make sure dialing 9 isn't going out POTS first; that would confuse the issue.