Disclosed is a system having a power input line. A power supply facility provides the system with a combined set of signals including a power signal and a status signal over the power input line.Additionally, disclosed is a system having at least two power input lines. Uninterruptible power supply facilities provide the system with combined sets of signals including a power signal and a status signal over the power input lines. Each combined set of signals includes a unique UPS identifier, which can be used to determine whether power sources for power input lines are unique.