Our interface to the telephone company network is the single-line telephone set. It stands to reason that we need to connect this set to the telephone company central office (CO). The pair of twisted wires running from the telephone company’s CO is called the local loop unbundling. Each subscriber, or customer, is delivered at least one pair of wires per telephone line. (more…)

The telco’s company’s company uses a variety of connections to bring the service to the customer locations. The typical connection is the two-wire service that we keep talking about. This two-wire interface to the network is terminated in a demarcation point, as required by law. The DEMARC is the point of least penetration into the customer’s premises, typically within 12 inches of where the telco’s company cable comes up into the building. (more…)