Mine's been weird. After rebooting the grandstream, I was able to finally call in. However; when I answered it, I only got a fast busy. After POWER-Cycling the grandstream, now I can answer calls. Also; a couple times (Not very much); I'd answer the phone and could talk, but the Cloned line continued to ring. But that hasn't happened much. "I think it's gremlins". Later.... mike.....