2. Access networks based on twisted copper pairs

2.1 Telephone access network

The traditional telephone network uses circuit switching, hence its name "Public Switched Telephone Network" (PSTN) . Each telephone network subscriber is connected via a twisted copper pair to a line interface on a local exchange (LSE) or a routing autonomy switch (RAS).

The term local loop refers to the terminal part of the telephone network where, in the event of a call, there is metallic continuity between the user's installation and the CL...