The replacement style might vary based on whether you have a combination battery backup/power supply or two separate units. The separate units take a 7.5 ampere-hour 12 volt sealed battery (7.25 AH or greater is fine).
Or you can get a cheaper generic replacement here: »
www.batterymart.com/p-12 ··· -f2.htmlOr here: »
www.batteriesplus.com/pc ··· .5F.aspxOr even look on eBay ...
Or you might even be able to buy one from FairPoint - but good luck with that.
Tony