I was just checking Polycom online support because I have a 2W doing (or not doing) the same thing. I'm going to try the tip above. However there's a notice on the Polycom site that this model needs a software update to alleviate this problem if you have an older unit. To check, press MENU, chose THIS PHONE, and then SYSTEM INFORMATION. IF the DSP version is 1.600 or lower an upgrade might help.

I thought I was smart, and then I got into telephones...