I made a quick visit to a condo that formerly had Verizon TV and Internet. Current tenant is using Xfinity. While tracking down a complaint of "bad Internet", I discovered a Verizon branded small, black box hiding under a radiator. Sorry, I didn't log the model number. This box was connected to the LAN and the port lights indicated that it was active. On site, I assumed that this was some sort of WiFi extender, but I suppose it could have been a cellphone extender of some sort.

I disconnected and powered down this box and the cell connection still seemed OK. Does anyone have any experience with this sort of "box" and what its function might have been?