A question was asked about Cox cable modems and the need to do a custom routing to gain a external IP address The router is a Cisco DPQ3212 this one has VOIP. VOIP needs a IP address so you cannot by default turn off NAT or do a Transparent Bridge because the VOIP would need to be set up externally on another device, not inside the modem. also FYI VOIP models usually have a battery to run the phone/modem during power outages/emergency, but if you edit the config and pull the power to reboot as I did, it kept running on battery and never changed till I removed the battery—live & learn. You can do some port forwarding but I have not tried it yet. If you need/whine to Cox and they will provide a two piece VOIP and standard non VOIP modem but I have not seen what they are using for that yet, but that is what was done on this system to get a public IP address for a camera system.
Non-VOIP models can usually be bridged and port forwarded in a similar way to Century Link DSL modems.
For business accounts they generally run two cables, one for phone only, and one for internet but with a multiple static IP addresses available at the modem.
Cable modems have two configurations and only one available to the user but with limited settings the other is sent to the modem on boot by TFTP from the cable company to set the speed and port information
