I had the DKT station settings set to CO Line & Ringing and Idle. The system started not always going to the ringing line when a call came in. They would pick up the phone and hear a dial tone, hang up and the ringing would continue. They would answer it again and some one would be there. ( Not sure if they pushed the blinking line button at this time to get the call.) I tried the above things to remedy this with no results. Thought I would turn off line ringing feature, then they would have to push the Line button to get a call. This works except for wireless headset from across the room. (I forgot about the headset.) Would like to know why the line ringing feature quit in the first place. I hope I have made this problem more clear. Thanks, Lyle