Competitive local exchange carrier

A competitive local exchange carrier (CLEC), in the United States and Canada, is a telecommunications provider company (sometimes called a "carrier") competing with other, already established carriers (generally the incumbent local exchange carrier (ILEC)).

Local exchange carriers (LECs) are divided into incumbent (ILECs) and competitive (CLECs). The ILECs are usually the original, monopoly LEC in a given area, and receive different regulatory treatment from the newer CLECs. A data local exchange carrier (DLEC) is a CLEC specializing in DSL services by leasing lines from the ILEC and reselling them to Internet service providers (ISPs).

CLECs evolved from the competitive access providers (CAPs) that began to offer private line and special access services in competition with the ILECs beginning in 1985. The CAPs (such as Teleport Communications Group (TCG) and Metropolitan Fiber Systems (MFS) deployed fiber optic systems in the central business districts of the largest U.S. cities (New York, Chicago, Boston, etc.) A number of state public utilities commissions, particularly New York, Illinois, and Massachusetts, encouraged this competition. By the early 1990s, the CAPs began to install switches in their fiber systems. Initially, they offered a "shared PBX" service with these switches and interconnected with the ILECs as end users rather than as co-carriers. However, the New York Public Service Commission authorized the nation's first CLEC when it required the New York Telephone (the ILEC) to allow Teleport Communications Group's switches in New York City to connect as peers. Other states followed New York's lead so that by the mid-1990s most of the large states had authorized local exchange competition.

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