How does a wired landline work with ATT Fiber?

If you want to use the homes existing wiring and jacks you'll have to back feed the phone line from the modem to the NID and connect it to the homes wiring, after removing the phone company old feed. 

Okay, maybe I asked the wrong question.

Can I keep my landline if I upgrade to ATT Fiber?

I'm not sure, but I doubt it. Once digital is installed POTS goes away.

To be clear, yes you can keep your landline, it will just be digital, not POTS, but it’s still considered a landline, it’s not wireless. That also means backup power is supplied locally should power go out, not by the central office. I converted from POTS to digital (not fiber, though) nearly 10 years ago and they initially installed a backup battery which has long since died and ATT no longer provides replacements. In other words, my landline goes out if I lose power now.

Back to my original statement, you can use it as you always have. I think the wireless you're talking about is a cordless phone system so you don't have to feed the homes wiring. I prefer the homes wiring. 

Thanks All. 

What has been mentioned, no phone if power is out, is the reason I want to keep the landline. 

My phone is available during power outages, which is how I can contact the power company to report and obtain updates. 

I will confirm with ATT. I am willing to do their update if and only if I can retain the wired landline service. 

You could always put a battery back up on it.