On Sunday, July 1, 2018 at 5:34:39 PM UTC-4, Wade Garrett wrote:
I want to ditch my landline and have looked at throe multi-handset
cordless phone systems sold by ATT, Panasonic and others that link via
Bluetooth to your cell phone. When your cell rings, you can answer it on
any one of the cordless handsets that you leave if different rooms of
your house.

Problem is though, the way my house lays out, cordless phone coverage
just doesn't reach far enough.

So what Im looking for is some kind of adapter/interface device that
will allow the cell phone to link to the houses phone wiring so I can
connect an ordinary corded phone to the phone jacks that are in most
rooms and answer my cell there.

Ever hear of one- or got another solution?

Are you sure those cordless systems you're looking at won't span the
house? The cordless phones I've had go all across the house, outside
for 50ft+. Buy one from someplace where you can take it back if it
won't cover the house. I would think the bluetooth link which I guess
is between your cell phone and the base would be the weak link, ie
you'd have to leave the cell phone within a room or so of the base.