On its website, Cox also maintains a list of modems customers can buy from third-party vendors that will be compatible with its service. Most customers already have the newer equipment, Caudle said.

The local cable television company says a few of its Internet customers with computer communications hookups dating back nine or more years must buy new equipment.

Not compatible with RCN. No cable modem is compatible with fiber optic, DSL, or satellite services, available from Verizon, AT&T, CenturyLink, Frontier, and others.) ...

The Arris SURFboard SB6141 cable modem is the best choice for most people because it's compatible with six of the eight biggest US cable ISPs—including the top three—as well as Cox.

The upgrade raised connection speeds for customers with two of the three Internet packages that Cox offers, and those modems are not compatible with the higher speeds.