(plural cable modems)
- (Internet) A modem that connects a personal computer to a fibreoptic cable, typically one used by a digital television system to provide broadband access
cable modem - Computer Definition
A modem designed to support high speed data communications over hybrid fiber/coax (HFC) CATV networks. Cable modems are positioned at the customers' premises and in a cable modem termination system (CMTS) at the service provider's headend. The initial Data over Cable Service Interface Specification (DOCSIS), released in 1997, standardized cable modems. Continuing research and development efforts directed at cable modems and related CATV network standards are largely the responsibility of CableLabs. See also CableLabs, CATV, CMTS, DOCSIS, HFC, and modem.
A technology for connecting users to the Internet through the TV-cable network and has the advantage of high-speed bandwidth 10–50 times as high (up to 5 megabits per second) as dial-up modems, which have 56 kilobits per second and use the telephone networks. TV-cable providers have to upgrade their network infrastructure to offer the service, whereas the dial-up modems need just a telephone line for connectivity. An alternative to the usage of cable-modems is DSL (Digital Subscription Line). DSL makes use of existing telephony lines and achieves approximately the same transmission speeds as cable modems.
See Also: DSL Modem; Network.
A device used to connect one or more computers to a cable company's Internet service. The same coaxial cable coming into the house or office also provides TV and voice over IP (VoIP) service. Compared to analog dial-up, cable Internet dramatically increased the bandwidth between the user's computer and the Internet (see broadband). In order to prevent residential customers from hosting high-traffic Web servers, the cable's upload speed is generally much slower than the download speed. In addition, the cable company may routinely change the IP address assigned to the modem (see DDNS). Connect Via Ethernet or USB Cable modems typically connect to a computer or router via Ethernet; however, some cable modems connect to one computer via USB. Cable Internet is a shared service, and the speed will vary depending on how many customers are sending or receiving data on that cable segment at the same time. For example, when kids come home from school in the afternoon, users in the neighborhood may experience slower speeds. See DOCSIS and Internet appliance.