It doesn't. Reeftronics polls your apex every 30 minutes. If it gets no connection, you get a notification. Either way you know something is up.
If you have an apex and you haven't registered at reeftronics, you really should.
There are cases where the modem or the router is acting up, you get the notification too. ;-) 1 stone 2 birds I think.
I also have an cheap IP camera to kind of verify certain aspect from a different angle of the current conditions. Also nowadays the electricity companies have up to date information if the power is out at an area. TBH, in my area that is very reliable as people call them within minutes so their Web site will show that. They are working on sending txt and messages if your power is down also. Nowadays with the smart meters which they installed 1 in the back at my place, this is very feasible. I don't know why that feature is still not available at my area :)