ARRIS Cable Modem Question

[YARDofSTUF]

Friend of mine recently got Comcast cable and the VOIP phone deal, I think the ARRIS 401 modem, deffinetly a ARRIS.

My question is does this modem have some kind power backup for the phone lines, because we unplugged it once and he lost the phone connection, but later on we unplugged it again and the phone line was still good.

Thanks.

[YARDofSTUF]

Well incase anyone else stumbles on to this wondering, it deffinately does have a battery for the phone line.