the CyberPower UPS is an ok product at the low end of the UPS market. The RJ12 pass-through is a bit dodgy, not sure if it works - ill have to test it with a cable tester. Otherwise I am good with it, as I have been with ot her CyberPowewr products. Ill use it on a modemand should protect it and keep the modem running during short power outs.