APC Smart-UPS – The Smart-UPS is a series of enterprise-level uninterruptible power supplies (UPS) made by American Power Conversion (APC).[1] Most of the units have a SmartSlot (with the exception of SC and SMC series) which accepts an optional interface card providing features ranging from network connectivity to temperature and humidity monitoring.[2] With the exception of RT and SRT series, Smart-UPS units are line-interactive UPS systems, only running their inverters when the grid power is unavailable.