Outside plant

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In telecommunication, the term outside plant has the following meanings:

In civilian telecommunications, all cables, conduits, ducts, poles, towers, repeaters, repeater huts, and other equipment located between a demarcation point in a switching facility and a demarcation point in another switching center or customer premises.

Note: The demarcation point may be at a distribution frame, cable head, or microwave transmitter.

In DOD communications, the portion of intrabase communications equipment between the main distribution frame (MDF) and a user end instrument or the terminal connection for a user instrument.

[edit] Context

It takes a lot to connect dozens or millions of telephones together, including people and hardware. Hardware that stays in place (not trucks or screwdrivers) is called "plant." Some items of plant can be centralized and kept indoors in the telephone exchange. This is called Inside plant. Other equipment, such as wires to connect a phone to its exchange, or optical fibers to connect exchanges to each other, must be outdoors, hence is called Outside plant. Outside plant is made to be rugged. Core network plant is often arranged in diversity schemes including SONET rings to avoid single failure points.

The CATV industry also divides its fixed assets between Head end or inside plant, and outside plant. The electric power industry sometimes uses the term "outside plant" to refer to electric power distribution systems.

[edit] Copper access network

In civilian telecommunications, the copper access network (also known as the local loop) typically consists of the following elements:

In-house wiring that connects customer premises equipment to the demarcation point.
One or more twisted pairs connect the demarcation point to a streetside cabinet or Serving area interface.
The streetside cabinet contains a distribution frame.
The streetside cabinet is connected to the main distribution frame, located at the central office, by one or more cables which together contain hundreds of copper twisted pairs.
Jumper cables are installed on both the MDF and the streetside distribution frame.
Active equipment (such as a POTS or DSL line circuit) can then be connected to the line in order to provide service, but this is not considered part of outside plant.