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Cable Modem

As the name suggests, cable broadband uses the cable television infrastructure. Cable access is similar to the DSL approach used by telephone companies—the difference being the cable service makes good use of the cable TV company’s coaxial cable existing network while DSL service leverages an existing telephone company’s plant. The connections between the cable company office (called the ‘headend’ as opposed to the Central Office for a telephone company) and the customer’s premise is either a pure cable run or  a hybrid fiber coaxial (HFC) facility (i.e., a network that uses both fiber and coaxial lines).

In discussions regarding cable broadband, you will often hear the term DOCSIS. Data over Cable Service Interface Specification (DOCSIS) is the international telecommunications standard that permits the addition of high-speed data transfer to an existing Cable TV (CATV) system. Due to the design of coaxial and fiber cable lines, cable speeds tend to be higher than traditional DSL speeds. Cable speeds currently range up to 100 Mbps. The maximum distance from the nearest headend that cable service can be offered is also typically much greater than with DSL service. However, cable lines are not nearly as ubiquitous as telephone lines. There may be installation charges for installing cable to new homes, and some homes may be too far from the nearest cable system for installation to be economically feasible.