[Mikeod]

That modem is a special modem that connects to your in-house phone wiring as well as provide internet service. When I added digital voice I had my own cable modem and I had to change to Comcast's modem. I could have kept my own modem for internet and rented the one for digital voice, but the one for digital voice also did internet, so I'd be paying the same anyway. Looks like you can get it at Best Buy. All the ones on eBay are used or refurbished or incomplete (no backup battery or power cord). If anything goes awry with phone or internet service and you have your own modem, they charge a service call to investigate the problem. With their modem, there is no charge.