Modem and router compatible with Charter?

I need a modem that will work with Charter, just for purchase with no rent. Who has one.

Motorola Surfboard 6120, HERE is Charter listed as compatible, but has only a single gigabit RJ45 connector so you would need a good router behind it. Probably the best single product solution is the SURFBOARD 6580, which should be compatible and has 4 gigabit ports and N wireless and most of the router functions that you could want short of using a distinct unit that would allow a dd-wrt firmware upgrade.