Demarc

Information about Demarc

Old and new style demarcation points in a home built in 1945. A splitter for a DSL modem has been plugged into the modern demarc (on the right). One line passes through a DSL filter before going to the old demarc, and from there to the rest of the house.

In telephony, the demarcation point is the point at which the telephone company network ends and connects with the wiring at the customer premises. A demarcation point is also referred to as the demarc, DMARC, MPOE, or minimum point of entry.

History

Prior to the Bell System divestiture on January 1, 1984, American Telephone & Telegraph Company (AT&T) through its Bell System companies held a natural monopoly for telephone service within the United States. AT&T owned the local loop, including the telephone wiring within the customer premises and the customer telephone equipment. A similar arrangement existed with smaller, regional telephone companies such as GTE. As a result of deregulation of the telephone system, unbundling of the local loop, and lawsuits by companies wishing to sell third-party equipment to connect to the telephone network, there was a need to delineate the portion of the network which was owned by the customer and the portion owned by the telephone company or the common carrier. Where the portions meet is called the demarcation point.

Equipment

A Bell Canada demarcation point. The fuses are located on the left and have hex heads for easy removal. A test jack is attached nearby so the homeowner or tenant can verify if the inside wiring is at fault.

The demarcation point varies from building type and service level. In its simplest form, the demarcation point is a junction block where telephone extensions join to connect to the network. This junction block usually includes a lightning arrestor (which requires a wire to earth ground.) In multi-line installations such as businesses or apartment buildings, the demarcation point may be a punch-down block. In most places this hardware existed before deregulation.

The modern demarcation point is a device defined by FCC rules (47 C.F.R. Part 68) ^[1] to allow safe connection of third-party telephone Customer-premises equipment and wiring to the Public Switched Telephone Network (PSTN). It is a square, weatherproof housing which contains the wiring junction. It is usually placed for easy access by a technician. It also contains a lightning arrestor, fuse and test circuitry which allows the carrier to remotely test whether a wiring fault lies in the customer premises or in the carrier wiring, without requiring a technician at the premises. The demarcation point has a user accessible RJ-11 jack and small loop of telephone cord connecting to the jack by a modular connector. When the loop is disconnected, the on-premises wiring is isolated from the telephone network and the customer may directly connect a telephone to the network via the jack to assist in determining the location of a wiring fault. In most cases, everything from the central office to and including the demarcation point is owned by the carrier and everything past it is owned by the property owner.

As the local loop becomes upgraded, with fiber optic and coaxial cable technologies sometimes replacing the original unshielded twisted pair to the premises, the demarcation point has grown to incorporate the equipment necessary to interface the original premises POTS wiring and equipment to the new communication channel.

References

1. ^ "[1] Federal Communications Commission.

A telephone company (or telco) provides telecommunications services such as telephony and data communications. Most of the largest telcos are or were at one time nationalized or state-regulated monopolies. These monopolies are often referred to, primarily in Europe, as PTTs.
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The break up of AT&T was initiated in 1974 by the U.S. Department of Justice antitrust suit against the telephone monopoly. Under the terms of a settlement finalized on January 8, 1982, "Ma Bell" agreed to divest its local exchange service operating companies, in return for a
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American Telephone & Telegraph Company, in its later years simply AT&T Corporation, provided voice, video, data, and Internet telecommunications and professional services to businesses, consumers, and government agencies.
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The Bell System was a trademark and service mark used by the United States telecommunications company American Telephone & Telegraph Company (AT&T) and its affiliated companies to co-brand their extensive circuit-switched telephone network and their affiliations with each other.
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United States

Sherman Antitrust Act
Clayton Antitrust Act
Robinson-Patman Act
Federal Trade Commission Act
Essential facilities doctrine
Noerr-Pennington doctrine
Rule of reason

Europe

European Community
competition law

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In telephony, the local loop (also referred to as a subscriber line) is the physical link or circuit, that connects from the demarcation point of the customer premises to the edge of the carrier, or telecommunications service provider, network.
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On-premises wiring: Customer-owned metallic or optical fiber communications transmission lines, installed within or between buildings.

Note: On-premises wiring may consist of horizontal wiring, vertical wiring, and backbone wiring, and may extend from the external
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GTE Corporation

Defunct
Founded 1918
Headquarters Irving, Texas, USA

Industry Communications Services
Products Internet access, Local wireline and wireless telecommunication services
Website www.verizon.
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Local loop unbundling (LLU) is the regulatory process of allowing multiple telecommunications operators use of connections from the telephone exchange's central office to the customer's premises.
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Hush-a-Phone v. FCC was a seminal ruling in United States telecommunications law decided by the DC Circuit Court of Appeals on November 8, 1956. Hush-a-Phone Corporation marketed a small, cup-like device which mounted on the speaking party's phone, reducing the risk of
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worldwide view of the subject.
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A common carrier is an organization that transports persons or goods, and offers its services to the general public.
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An extension telephone is an additional telephone wired to the same telephone line as another. In middle 20th century telephone jargon, the first telephone on a line was a "Main Station" and subsequent ones "Extensions".
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lightning rod (or lightning protector) (USA) or "lightning conductor" (UK), is a metal strip or rod, usually of copper or similar conductive material, a lightning safety measure designed to protect tall or isolated structures (such as the roof of a building or the mast of a
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In electrical engineering, the term ground or earth has several meanings depending on the specific application areas. Ground is the reference point in an electrical circuit from which other voltages are measured, a common return path for electrical current (
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A punch block (also punchblock, punchdown block, quick-connect block and other variations) is a type of electrical connection often used in telephony.
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Federal Communications Commission

Logo

The FCC's official seal
Agency overview
Formed June 19, 1934
Preceding Agencies Federal Radio Commission

Annual Budget

Agency Executive
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Customer-premises equipment or customer-provided equipment (CPE) is any terminal and associated equipment and inside wiring located at a subscriber's premises and connected with a carrier's telecommunication channel(s) at the demarcation point ("demarc").
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The public switched telephone network (PSTN) is the network of the world's public circuit-switched telephone networks, in much the same way that the Internet is the network of the world's public IP-based packet-switched networks.
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fuse, short for 'fusible link', is a type of overcurrent protection device. Its essential component is a metal wire or strip that melts when too much current flows. When the metal strip melts, it opens the circuit of which it's a part, and so protects the circuit from excessive
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Modular connector is the name given to a family of electrical connectors examples of which are pictured. These connectors were originally used in telephone wiring. Even though they are still used for that purpose they are used for a variety of other things as well.
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worldwide view of the subject.
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In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls.
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An optical fiber (or fibre) is a glass or plastic fiber designed to guide light along its length. Fiber optics is the overlap of applied science and engineering concerned with such optical fibers.
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Coaxial cable is an electrical cable consisting of a round conducting wire, surrounded by an insulating spacer, surrounded by a cylindrical conducting sheath, usually surrounded by a final insulating layer (jacket).
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Twisted pair cabling is a form of wiring in which two conductors are wound together for the purposes of canceling out electromagnetic interference (EMI) from external sources, electromagnetic radiation from the UTP cable, and crosstalk between neighboring pairs.
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Point of appearance is a generic term for any point in a telephone/data circuit from which a technician can test or pull stats. Some appearances are virtual, such as a Digital cross connect system computer terminal.
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network interface device (NID) is interchangeable with network interface unit (NIU)

Meanings of the term

A network interface, also commonly referred to as a smart jack, is typically in the basement, first floor telco room, garage, or even outside the
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In Telephony, a Main Distribution Frame (MDF or Main Frame) is a signal distribution frame for connecting equipment (inside plant) to cables and subscriber carrier equipment (outside plant).
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