Interesting. I'm sure it's correct, but it makes me wonder about the output quality of these devices. If the output of an UPS is so significantly different from

Interesting. I'm sure it's correct, but it makes me wonder about the output quality of these devices. If the output of an UPS is so significantly different from regular utility power that it's unsuitable as input for an UPS, then it must be of a worse quality and unsuitable for the expensive equipment it's supposed to power ? I do understand the logic that chaining UPS will cause interesting things to happen when power is restored and the downstream UPS can then overload the upstream UPS because it will incur additional load when charging its battery, which could trigger overload protection in the upstream device.