This x-13 had been having some problems. Bad cable pair. The phone was resetting and turning on by itself etc. I changed cable pairs and once I had the phone back in service and was checking everything. I noticed when I pressed line 1 to make a call, I got a busy signal and the display says "line unavail". I checked programming. Under line assignments line 1 is set to Y. Under receive assignment line 1 is set to Y. Under ring assignment line 1 is set to Y. I took the phone and plugged it into x-10 and it worked fine. I reset the system. Nothing helps. Any other ideas?