cable modem

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cable modem

[¦kā·bəl ¦mō‚dem]
(electricity)
A device that converts the signals used in a computer to signals that can be transmitted over cable television networks, and vice versa.

cable modem

(communications, hardware)
A type of modem that allows people to access the Internet via their cable television service.

A cable modem can transfer data at 500 kbps or higher, compared with 28.8 kbps for common telephone line modems, but the actual transfer rates may be lower depending on the number of other simultaneous users on the same cable.

Industry pundits often point out that the cable system still does not have the bandwidth or service level in many areas to make this feasible. For example, it has to be capable of two-way communication.

See also: DOCSIS.

cable modem

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.


A Cable Modem System
At the cable company plant, Internet packets are combined with standard TV programming. See CMTS.