When you use a phone or internet to call or text people, the signal goes through wires and machines called networks. A competitive local exchange carrier (CLEC for short) is a company that sets up their own network of wires and machines to compete with the big companies that already have networks, like AT&T or Verizon. Kind of like how two kids might try to sell lemonade on the same street corner. The CLEC's network is called a "local exchange" because it's set up in a specific area, like a neighborhood or city. They try to offer better prices or options than the bigger companies to get people to use their network instead.