cable modem 
Cable modems provide high-speed Internet access over cable TV networks (which rely primarily on fiber-optic or coaxial cable). The most popular devices for broadband Internet access, cable modems support very high data rates--much higher that those allowed by cable ISPs, which tend to restrict user accounts to roughly 1 megabit per second (approximately 20 times faster than a dial-up modem). Speed varies depending on how many subscribers are logged on to the network in a particular locality.