What is this box? Asking for a friend who lives 1000 miles away. Her doorbell is on another wall & her CO2 detector is a smoke alarm combo. It makes a weird noise & her dog reacts to it, waking her up at all hours.

Why have I seen this post before...

http://dollars-bbs.org/tech/res/1386355282.html

*twilight zone theme song fades in*

It does seem to be a doorbell, whether it's actually in use or not. A lot of people seem to come to the internet after the transformer developes a buzz or hum. It can be replaced.

I saw the other post first but this didn’t look like the doorbell to me that was in the other pic.

I found a couple similar inquiries on other websites as well and they all conclude with a doorbell console with a noisy transformer. So that's really all I got. The buzzing is a dead giveaway. And I really don't think it's something like a circuit breaker console.

https://www.styleforum.net/threads/help-with-a-buzzing-noise-in-my-house.325913/

https://www.justanswer.com/electrical/5kwzk-door-bell-makes-constant-hum.html

https://www.picrail.com/l/4ciy9w/what-is-the-white-box-on-the-wall-in-the-hallway

http://answers.angieslist.com/Who-I-call-find-loud-continuous-humming-noise-home-q42545.aspx

http://72.52.242.200/loud-buzzing-doorbell-box-closet-furnace-install-q151932.aspx

https://energytoday.biz/blog/4-reasons-your-circuit-breaker-panel-is-buzzing