Which statement is true regarding offline UPS systems?

The statement that offline UPS systems directly route incoming power to devices until a power interruption is correct. Offline UPS systems, also known as standby UPS systems, are designed to provide basic power protection. During normal operation, these systems supply power directly from the utility source to the connected devices. Only when there is a power failure or significant voltage fluctuation does the UPS switch to battery power, ensuring that the devices are protected from interruptions. This switching process typically happens very quickly, but it is not instantaneous, which means that there is a brief moment of switch-over.

In contrast, other options present different characteristics. Continuous power without interruption is a feature of online UPS systems, which continuously convert power and provide an uninterruptible supply. Offline UPS systems are not the ideal choice for all commercial settings, as their response time may not be sufficient for critical applications needing immediate switch-over. Lastly, while UPS systems do require battery maintenance, the statement regarding constant battery charging may not accurately depict how offline types operate, as their batteries are only engaged during a power failure, unlike online systems where charging occurs continuously.