Editing Demarcation point (section)

===United States===
In the United States, the modern demarcation point is a device defined by [[Federal Communications Commission|FCC]] rules (47 C.F.R. Part 68) <ref>{{cite web|url=http://www.part68.org |title=Administrative Council for Terminal Attachments |website=Part68.org |access-date=2016-04-28}}</ref> to allow safe connection of third-party telephone [[customer-premises equipment]] and wiring to the [[Public Switched Telephone Network]] (PSTN).

[[Image:Network interface device ameritech.jpg|thumb|upright|left|Two [[network interface device]]s]]
The modern demarcation point is the [[network interface device]] (NID) or intelligent network interface device (INID) also known as a "smartjack".<ref>{{cite web|url=http://www.integratednetworkcable.com/cabling-and-network-installation/demarc-extension-services |title=Demarc Extension Services Nationwide T1 Circuit Extensions |website=Integratednetworkcable.com |access-date=2016-04-28}}</ref>  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 (electrical)|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 (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]].

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 [[telephone exchange|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 [[Plain old telephone service|POTS]] wiring and equipment to the new communication channel.

Demarcation points on houses built prior to the [[Bell System divestiture]] usually do not contain a test jack. They only contained a spark-gap surge protector, a [[Ground (electricity)|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]] of telephone wires on the wall next to a series of boxes with [[RJ48]] jacks for [[Digital Signal 1|T-1 line]]s. Each business or individual customer can expect their own separate box for internet access T-1 lines.

==== <span id="Demarc extension">Demarcation point extension</span> ====
[[File:Demarc Extension Single Segment.jpg|thumb|left|upright=1.6|Demarcation point 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|Customer Premises Equipment]] (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.<ref>{{cite web|url=http://www.integratednetworkcable.com/cabling-and-network-installation/demarc-extension-services |title=Demarc Extension Services Nationwide T1 Circuit Extensions |publisher=Integratednetworkcable.com |access-date=2016-04-28}}</ref>

A demarc extension became an important factor to consider in a building's telecommunications infrastructure after the 1984 [[Bell System Divestiture|deregulation of AT&T]] as well as the supplemental FCC rulings of 1991, [[Telecommunications Act of 1996|1996]] and 1997. Preceding these rulings, the Bell System Companies held a monopoly and did not allow an [[interconnection]] with third party equipment. The [[incumbent local exchange carrier]]s (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.