On Tue, 07 Jan 2014 14:52:02 -0500, Percival P. Cassidy wrote:

Our Panasonic DECT phones are on 1.9GHz, I'm almost certain -- not on
the common 2.4GHz WiFi frequency.

My problematic Panasonic KX-TG6441 cordless phone is also on 1.9 GHz,
as described on page 6 of this PDF:
http://farm4.staticflickr.com/3786/1...4ca30a30_o.png
http://service.us.panasonic.com/OPER...TG6431-MUL.PDF