The On-line UPS provides the highest level of power protection for the serious home office user. It does typically cost more, but like all electronic equipment today the cost is coming down as the technology advances. The true advantage to the on-line UPS is its ability to provide an electrical firewall between the incoming utility power and sensitive electronic equipment. While the off-line and line-interactive designs leaves equipment connected directly to the utility power with minimal surge protection, the On-line UPS provides an electronic layer of insulation from power quality problems. This is accomplished inside the UPS in several tiers of circuits.
