Recently released by Netgear, the CM500V is for Comcast XFINITY Voice customers. It's basically the same as the Netgear CM500 except it has a 2 telephone ports for voice service. The CM500V is currently only supported by Comcast.
The NETGEAR CM500V Cable Modem for Internet & Voice provides a connection to high-speed cable Internet and supports 2 phone lines. CableLabs® certified DOCSIS® 3.0 is 16X faster than 2.0 devices. Up to 680Mbps† download speed for streaming HD videos, faster downloads, and high speed online gaming—ideal for XFINITY® from Comcast Double and Triple Play service plans. A Gigabit Ethernet port provides faster access and downloads. Save money over time by owning your cable equipment and avoiding monthly rental charges from your Internet Provider.