I doubt the adix port 001 is bad in backplane, check amp cables, block punch downs etc.. confirm config programming (generally port 001 is programmed as attendant; 001, 001), make sure it is programmed for KP 129. Also there can be problems with the adix if you have a an attendant phone with a dss assigned to it and you unplug/replug the phone and dss in the wrong order (the dss tries to be the phone and vise-versa). To correct you may have to reload config and reset system with phone/dss in proper port locations. Hope this helps.