https://www.cnet.com/news/first-alert-now-has-a-smart-doorbell-the-onelink-bell-ces-2019/

It also works with other First Alert gadgets like the Onelink Safe & Sound smoke and carbon monoxide detector. First Alert says if you don't have your phone handy to see who's at your door, that you can use your Safe & Sound detector's integrated microphone and speaker to talk with them.

First Alert says the Onelink Bell will also work with Amazon Alexa and Google Assistant.