Re: Replacement battery for Home Security system's keypad.

I was told several times by Comcast techs that they will replace batteries in the devices, except for the thermostat, which you can do yourself (3 AA'S). Call for an appointment, and make sure the service is free.
The keypad has two CR2 batteries, that you can purchase and replace on your own if you wish...here are instructions for the keypad...
http://na.smc.com/wp-content/uploads/2011/07/SMCWK01-Z_Key_Pad_Quick_Start_Guide_Final_031011_A5.pdf
I have an extra keypad if you need it...send me a PM.