On Mon, 06 Jan 2014 23:48:17 -0500, Ralph Mowery wrote:

Have you added anything like a wireless router for the internet ? Sometimes
phones and other wireless devices will interfear with other.

Yes. There is lots of WiFi in the house.

There are also other cordless bases and phones on other lines, e.g.,
http://farm3.staticflickr.com/2873/1...fdd2467b_o.gif

For example, this Panasonic KX-TG6671 seems to work just fine though:
http://farm3.staticflickr.com/2806/1...52b01faf_o.gif