In theory, an Uninterruptable Power Supply (UPS)’s workings such as the APC SmartUPS 750 in connection with an attached PC are trivial: when power fails and battery capacity runs low, the PC is shut down. When power returns, the PC is turned on again. In reality, there can be confusing messages such as UPS Rbt… Continue reading APC SmartUPS 750, apcupsd and power failure: what exactly happens, where “UPS Rbt off” and “UPS StayOff” come from and which delays are configurable and which are not