pissing_noises

Aiphone video intercom

Another thought, if your additional router is just for wifi then plug in via a LAN port not its WAN port, then it's just for wifi and won't do any routing. You'll want to disable DHCP on it so it won't fight with your ISP router.

It all really depends on what your ISP gives you, if they give you a modem-router combo device then that has to stay in the basement, and all the home runs connect to it or your switch and then to it.

If they give you a modem and a separate router like an eero or something, that separate router could go anywhere as long as it runs back to the modem over one of the cats. You could also connect your own routers WAN port to one of the combo modem-rourers LAN ports and then ignore it from there, unless you need to change port rules or whatever. But your switch needs to be connected to your router not the ISP one, which ignores those home runs you put work in for.

The hierarchy is modem > router > switch > device.

Yea the wires should run to a central location. Wifi boosters typically repeat a wireless signal, but you can install wireless access points that are plugged in and can form a cohesive wireless network with proper handover and mesh, but you'd need to hire someone as that's more of a prosumer /professional thing. The wireless whole home coverage from your ISP is probably just going to be wireless repeaters.

If you don't have enough ports on your ISP modem just add a switch.

I never knew about the stairwells, that's cool.

Just want to clarify I'm not a fire alarm guy, although I do work alongside them and have picked up some stuff. Buildings are neat.

My guess is that it's going to turn your house into a chimney and feed the fire.

Usually in industrial fire systems, the system is set up to cut off HVAC or other air systems in order to contain the fire. Leaving them running increases the risk of feeding the fire or transporting hot ashes or cinders through the building, making things worse for the building and any occupants who haven't evacuated yet.