We supplemented our main cordless phone with three (3) GH41MS phones, giving us the flexibility of putting phones in areas of the house for convenience. We went to a digital system several months ago and all was well with the phones. Now the three extensions are displaying the message 'OUT OF RANGE' and the do not work. I placed my manuals in a safe place (so safe I can't find them) and I need to know if there is something I can do to salvage these phones.