Just got off the phone with an engineer; we spoke a bit about your concerns. He reassured me that if someone has unreliable power, it's perfectly OK to use a UPS. Just make sure that the UPS battery is replaced regularly. He brought this up when I mentioned that you were using your previous UPS for the past 4-5 years. An old battery in a UPS could result in the modem not getting the power it needs.
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