Outside Plant Infrastructure: Components and Systems

Elements of Outside Plant

Outside plant infrastructure encompasses all support systems necessary to identify, nurture, and protect communication streams. These elements are divided into three primary parts:

• Channeling: Consists of civil works, including pipelines, conduits, and inspection chambers.
• Lines: The physical network constituted by poles, cable laying, anchors, and support hardware.
• Connection: The union of cables, including terminal box distribution, network maintenance, transfer protection, joints, and adherence to work standards.

Telephone Exchanges

These buildings house transmission and switching equipment that enable communication between subscribers. They also contain power supply equipment and the Main Distribution Frame (MDF).

MDF (Main Distribution Frame)

The MDF serves as the point of union between the outside plant and the telephone exchange. Located in the central building—typically on the first floor near the equipment room and cable basement—the MDF contains racks with vertical and horizontal panels for cable management.

Common Telecommunications Terminology

• Easy Access Box: An aerial terminal box protected by a plastic enclosure, providing drop lines to subscribers.
• External Terminal Box: Boxes mounted directly on poles or walls to provide lines to subscriber homes.
• Drop Line: A double-line of iron-coated copper wires (A and B) encased in a plastic sheath.
• External Telephone Cable Box: A distribution point for primary and secondary cable pairs, where interconnections are made via bridges.
• Metal Poles: Structures used to support aerial telephone cables and drop lines; may also consist of wood, concrete, or rail materials.
• Aerial Telephone Cables: Cables featuring a polyethylene lining for excellent insulation and water resistance. These are built with an integrated messenger wire to support the weight of the cable, ensuring no physical force is exerted on the conductors.