Lectrician said:APC ups's have serial and USB interfaces to connect to a server. You can connect as many as you want to a network, and use one server to monitor the lot.
Even a mains contactor with a contact that rings a battery operated door bell in the supervisor's room when the mains to a rack fails.
It isn't rocket science and the time to install is short and the cost small compared to just a few minutes of system outage.......