Yes, you will need a modem. I don't know about Century Link, but I have a recent Motorola and it works very reliably. I restart it once in a while because it's suggested, but hasn't frozen yet. Think of the two this way: the MoDem (modulate-demodulate) converts the signal in the cable or whatever to a signal your computer can understand. If you wanted a single, hard-wired connection, you wouldn't need a router because it outputs to one Ethernet port. The router allows you connect multiple devices to the one router, whether wired or wireless. There are routers (and switches, but I won't get into that) that are only wired, for situations where there are multiple wired computers connected to one port. Hope that helps.