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telephony Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is i ...
, the demarcation point is the point at which the
public switched telephone network The public switched telephone network (PSTN) provides Communications infrastructure, infrastructure and services for public Telecommunications, telecommunication. The PSTN is the aggregate of the world's circuit-switched telephone networks that ...
ends and connects with the customer's
on-premises wiring On-premises wiring (customer premises wiring) is customer-owned telecommunication transmission or distribution lines. The transmission lines may be metallic (copper) or optical fiber, and may be installed within or between buildings. Premises ...
. It is the dividing line which determines who is responsible for installation and maintenance of wiring and equipment—customer/subscriber, or
telephone company A telephone company, also known as a telco, telephone service provider, or telecommunications operator, is a kind of communications service provider (CSP), more precisely a telecommunications service provider (TSP), that provides telecommunicat ...
/provider. The demarcation point varies between countries and has changed over time. ''Demarcation point'' is sometimes abbreviated as demarc, DMARC, or similar. The term MPOE (minimum or main point of entry) is synonymous, with the added implication that it occurs as soon as possible upon entering the customer premises. A
network interface device upTwo simple NIDs, carrying six lines each, on the outside of a building upA German copper phone line termination box called '' Abschlusspunkt LinienTechnik'' (APL, " Demarcation point") In telecommunications, a network interface device (NID; ...
often serves as the demarcation point.


History

Prior to
Federal Communications Commission The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdiction ...
(FCC) regulations separating the ownership of customer premises telecommunication equipment from the telephone network, there was no need for a public standard governing the interconnection of customer premises equipment (CPE) to the United States' telephone network, since both the devices and the “local loop” wiring to the central office were owned and maintained by the local telephone company. Concurrent with the transfer of existing "embedded" CPE to the customer (customers could buy new telephones at retail or could continue to lease their existing equipment from the company), it was necessary to provide a standardized way to connect equipment, and also provide a way to test the phone company's service separately from the customer's equipment. The ability of customers to buy and maintain their CPE and attach it to the network was stimulated by lawsuits by equipment manufacturers, such as the Hush-a-Phone v. FCC suit. Additionally, computer companies’ ability to offer enhanced services to customers was likewise constrained by the telephone companies’ control of all devices connected to the network. As the Bell telephone companies were themselves restricted from offering such enhanced services, there was little momentum to advance the state of the art. The newly developed equipment-network separation was codified in Part 68 of the Code of Federal Regulations in the United States and later in comparable regulatory standards in other countries. The physical and electrical interconnection is called the demarcation point, or Demarc, which includes one or more customer-accessible jack interfaces; previously, the interface was typically hard-wired and often in a telephone company-owned locked enclosure. The premises-vs.-network separation in the United States, insofar as it affected the former
Bell System The Bell System was a system of telecommunication companies, led by the Bell Telephone Company and later by the American Telephone and Telegraph Company (AT&T), that dominated the telephone services industry in North America for over one hundr ...
, was independent of AT&T's divestiture of the local telephone companies on January 1, 1984. However, CPE interconnection and
Bell System divestiture The breakup of the Bell System was mandated on January 8, 1982, by an agreed consent decree providing that AT&T Corporation would, as had been initially proposed by AT&T, relinquish control of the Bell Operating Companies, which had provided loc ...
were part of a larger restructuring of the domestic telecommunications industry which took place during the 1980s and are commonly, if inaccurately, seen as one event. The historical Bell System domination of the United States telecommunications industry was also the de facto standard for other telephone companies such as
GTE GTE Corporation, formerly General Telephone & Electronics Corporation (1955–1982), was the largest independent telephone company in the United States during the days of the Bell System. The company operated from 1926, with roots tracing furth ...
and other “independent” telephone companies.


Equipment


Canada

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 arrester A lightning arrester (alternative spelling lightning arrestor) (also called lightning isolator) is a device, essentially an air gap between an electric wire and ground, used on electric power transmission and telecommunication systems to protect ...
(which requires a wire to ground). In multi-line installations such as businesses or apartment buildings, the demarcation point may be a
punch down block A punch-down block (also punchdown block, punch block, punchblock, quick-connect block and other variations) is a type of electrical connection often used in telephony. It is named because the solid copper wires are "punched down" into short open ...
. In most places this hardware existed before deregulation.


United States

In the United States, the modern demarcation point is a device defined by
FCC The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdiction ...
rules (47 C.F.R. Part 68) to allow safe connection of third-party telephone
customer-premises equipment In telecommunications, a customer-premises equipment or customer-provided equipment (CPE) is any terminal and associated equipment located at a subscriber's premises and connected with a carrier's telecommunication circuit at the demarcation poi ...
and wiring to the
Public Switched Telephone Network The public switched telephone network (PSTN) provides Communications infrastructure, infrastructure and services for public Telecommunications, telecommunication. The PSTN is the aggregate of the world's circuit-switched telephone networks that ...
(PSTN). The modern demarcation point is the
network interface device upTwo simple NIDs, carrying six lines each, on the outside of a building upA German copper phone line termination box called '' Abschlusspunkt LinienTechnik'' (APL, " Demarcation point") In telecommunications, a network interface device (NID; ...
(NID) or intelligent network interface device (INID) also known as a "smartjack". The NID is the telco's property. The NID may be outdoors (typically, mounted on the building exterior in a weatherproof box) or indoors. The NID is usually placed for easy access by a technician. It also contains a lightning arrestor,
fuse Fuse or FUSE may refer to: Devices * Fuse (electrical), a device used in electrical systems to protect against excessive current ** Fuse (automotive), a class of fuses for vehicles * Fuse (hydraulic), a device used in hydraulic systems to protect ...
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 (a "test jack" or "demarcation jack"), which is connected directly to the telephone network, and a small loop of telephone cord connecting to the jack by a
modular connector A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such as in computer networking, telecommunication equipment, and audio headsets. Modular connectors were originally developed fo ...
. When the loop is disconnected, the
on-premises wiring On-premises wiring (customer premises wiring) is customer-owned telecommunication transmission or distribution lines. The transmission lines may be metallic (copper) or optical fiber, and may be installed within or between buildings. Premises ...
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 An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to ...
and
coaxial cable Coaxial cable, or coax (pronounced ) is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric ( insulating material); many coaxial cables also have a p ...
technologies sometimes replacing the original
unshielded twisted pair Twisted pair cabling is a type of wiring used for communications in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a single conductor or an untwisted bal ...
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. Demarcation points on houses built prior to the
Bell System divestiture The breakup of the Bell System was mandated on January 8, 1982, by an agreed consent decree providing that AT&T Corporation would, as had been initially proposed by AT&T, relinquish control of the Bell Operating Companies, which had provided loc ...
usually do not contain a test jack. They only contained a spark-gap surge protector, a grounding post and mount point to connect a single telephone line. The second wire pair was usually left unconnected and were kept as a spare pair in case the first pair was damaged. DEMARCs that handle both telephony and IT fiber optic internet lines often do not look like the ones pictured above. In many places several customers share one central DEMARC for a commercial or strip mall setting. Usually a DEMARC will be located indoors if it is serving more than a single customer. This may impede access. Outdoor ones provide easier access, without disturbing other tenants, but call for weatherproofing and punching through a wall for each new addition of wires and service. Typically indoor DEMARC's will be easily identified by a
patch panel A patch panel is a device or unit featuring a number of jacks, usually of the same or similar type, for the use of connecting and routing circuits for monitoring, interconnecting, and testing circuits in a convenient, flexible manner. Patch ...
of telephone wires on the wall next to a series of boxes with
RJ48 A registered jack (RJ) is a standardized telecommunication network interface for connecting voice and data equipment to a service provided by a local exchange carrier or long distance carrier. Registration interfaces were first defined in th ...
jacks for T-1 lines. Each business or individual customer can expect their own separate box for internet access T-1 lines.


Demarc extension

A demarcation point extension, or demarc extension is the transmission path originating from the interface of the access provider's side of a demarcation point within a premises and ending at the termination point prior to the interface of the edge
Customer Premises Equipment In telecommunications, a customer-premises equipment or customer-provided equipment (CPE) is any terminal and associated equipment located at a subscriber's premises and connected with a carrier's telecommunication circuit at the demarcation poi ...
(CPE). This may include in-segment equipment, media converters and patch cords as required to complete the circuit's transmission path to the edge CPE. A demarc extension is more correctly termed "Service Interface Extension", and may also be referred to as inside wiring, extended demarc, circuit extension, CPE cabling, riser cabling or DMARC extension. A demarc extension became an important factor to consider in a building's telecommunications infrastructure after the 1984 deregulation of AT&T as well as the supplemental FCC rulings of 1991,
1996 File:1996 Events Collage.png, From left, clockwise: A Centennial Olympic Park bombing, bomb explodes at Centennial Olympic Park in Atlanta, set off by a radical Anti-abortion violence, anti-abortionist; The center fuel tank explodes on TWA Flight 8 ...
and 1997. Preceding these rulings, the Bell System Companies held a monopoly and did not allow an
interconnection In telecommunications, interconnection is the physical linking of a carrier's network with equipment or facilities not belonging to that network. The term may refer to a connection between a carrier's facilities and the equipment belonging to ...
with third party equipment. The incumbent local exchange carriers (ILEC) and other local access providers are now mandated by federal law to provide a point where the operational control or ownership changes. This separation between the local access provider and the end user/subscriber is called the demarcation point within a facility (typically a short distance from the minimum point of entry). This then becomes the responsibility of the end user to extend their service to the CPE location within a facility to provide connectivity for service, requiring a service interface extension, or otherwise called a demarc extension.


United Kingdom

In the United Kingdom, the demarcation point occurs on the LJU master socket, whose wiring is partly owned by the customer, partly owned by the phone company. Other secondary sockets are the customer's property. Newer NTE-5 master phone sockets have a removable front panel: the front panel and its wiring is the customer's, while the rear wiring is Openreach's. The removable panel allows separation of these two parts and independent maintenance, and access to a test socket to determine whether line faults are in the customer's wiring or Openreach's (formerly BT's) external network.


See also

*
66 block 66 may refer to: * 66 (number) * One of the years 66 BC, AD 66, 1966, 2066 *66 (song), "66" (song), a song by Lil Yachty featuring Trippie Redd *66, a song by The Afghan Whigs, from the album 1965 (album), 1965 *Sixty-Six (card game), a German card ...
* 110 block *
Carterfone The Carterfone is a device invented by Thomas Carter. It manually connects a two-way radio system to the telephone system, allowing someone on the radio to talk to someone on the phone. This makes it a direct predecessor to today's autopatch. ...
*
Customer-premises equipment In telecommunications, a customer-premises equipment or customer-provided equipment (CPE) is any terminal and associated equipment located at a subscriber's premises and connected with a carrier's telecommunication circuit at the demarcation poi ...
* ''
Hush-A-Phone Corp. v. United States ''Hush-A-Phone v. United States'', 238 F.2d 266 (D.C. Cir. 1956) was a seminal ruling in United States telecommunications decided by the D.C. Circuit Court of Appeals. Hush-A-Phone Corporation marketed a small, cup-like device which mounted on t ...
'' *
Interconnection In telecommunications, interconnection is the physical linking of a carrier's network with equipment or facilities not belonging to that network. The term may refer to a connection between a carrier's facilities and the equipment belonging to ...
*
Main distribution frame 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). Overview The MDF is a termination point within the l ...
*
Network interface device upTwo simple NIDs, carrying six lines each, on the outside of a building upA German copper phone line termination box called '' Abschlusspunkt LinienTechnik'' (APL, " Demarcation point") In telecommunications, a network interface device (NID; ...
*
On-premises wiring On-premises wiring (customer premises wiring) is customer-owned telecommunication transmission or distribution lines. The transmission lines may be metallic (copper) or optical fiber, and may be installed within or between buildings. Premises ...
*
Point of appearance 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. Others are physical, like a pu ...
* Service termination point


References


External links


Demarc extension terminology



Telecommunications Act of 1996
{{Room Local loop Telephony equipment