When we gave up on DSL (the DSL provider failed to actually provide a connection too many times), the phone line went away with it. But that doesn't mean that the phone on the desk or such doesn't work. Both jmaynard and I have Google Voice numbers as well the cell numbers. And a little gadget made by Obihai allows those numbers to work with the wired phones in the house.
Overall this works out well. The Google number rings at home and the cellphones, so calls are unlikely to be missed. Since Jay uses the phone more than I do, he gets line 1 and I get line 2. The only thing I've found I that bothers me is that with just one phone in the office, on Jay's desk, it's a nuisance for us. If I need to use it (incoming or outgoing call) it seems to always happen when it makes it a problem for one or both of us.
The solution is, of course, to put a phone my desk and just have it connected to line 2. I did that not long ago when it was recalled the office phone outlet has a socket for a line 3 & 4. We patched things so that "Line 2" from the gadget is "Line 3" (Line 1 of the second socket) in the house. I used a typical slimline sort of phone for a week or two that way but it wasn't quite what I wanted. One issue was that the pushbuttons were on the handset, which gets a bit annoying in a world with pushbutton menus. That was recently remedied, with style.
Now on my desk is something that perhaps looks out of place: An upright style (AKA "candlestick") phone. It's not a historical item, but a modern replica with buttons. Those buttons are nicely arranged in dial style, however. And the phone is no lightweight. Not so much in features (it's just a phone, the fanciest thing it does is have redial) but in actual weight. It isn't going anywhere by mere chance. The earpiece is heavy enough for exercise - or to indicate that a call has gone on plenty long enough. Oh, and the ringtone is not a tone. It's a real bell ringing, in a very pleasant 'two short' style: *brrring* *brrring*