Demarcation Point

• Demarcation point (demarc): terminology used with lease lines and telephone equipment.
• • Today, with many other connectivity options such as broadband cable and fiber to the premises, the demarc has become the equipment that hands off service to the customer.
  • The technician will disconnect the rest of your network and test basic Internet connectivity.
  • Most problems can even be diagnosed from the home office of the provider, since all of the equipment has built-in diagnostics to reduce the number of technicians dispatched.
• • Leased lines like T1s and Integrated ServicesDigital Network (ISDN) lines have a mechanical jack called an RJ-48X (registered jack) at the patch panel.
  • When the RJ-48 is removed, a shorting block bridges the connection to create a loopback.
  • These mechanical jacks have largely been replaced with a device called a smart jack.