The ARRIS SURFboard TM822G is 2 products in 1: a DOCSIS 3.0 cable modem, capable of download speeds up to 343 Mbps, plus a 2-port telephony modem. Arris, the worldwide leader in cable modems, developed the TM822 for XFINITY from Comcast subscribers. Optimized for use with XFINITY from Comcast Internet & Voice service, it provides your connection to the Internet plus 2 telephony lines for Voice over IP (VoIP). battery backup options (sold separately) provide Peace of mind during power outages. Save on monthly rental fees and Buy your modem today!