Network interface device: Difference between revisions

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Latest revision as of 05:52, 4 August 2025

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[[file:apl germany.jpeg|thumb|upright|A German copper phone line termination box called ''[[:de:Abschlusspunkt Linientechnik|Abschlusspunkt LinienTechnik]]'' (APL, "[[Demarcation point]]")]]

In [[telecommunications]], a '''network interface device''' ('''NID'''; also known by several other names) is a device that serves as the [[demarcation point]] between the carrier's [[local loop]] and the customer's [[on-premises wiring|premises wiring]]. Outdoor telephone NIDs also provide the subscriber with access to the station wiring and serve as a convenient [[test point]] for verification of loop integrity and of the subscriber's inside wiring.

== Naming ==

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{{Main|Intelligent Network Interface Device}}

[[file:Network Interface Unit.jpg|thumb|upright|Three smartjacks for [[Digital Signal 1|T-1]] circuits, in two shelves; a [[66 block]] is on the left]]

Several types of NIDs provide more than just a terminal for the connection of wiring. Such NIDs are colloquially called ''smartjacks'' or [[Intelligent Network Interface Device]]s (INIDs) as an indication of their built-in "intelligence", as opposed to a simple NID, which is just a wiring device. Smartjacks are typically used for more complicated types of [[telecommunications service]], such as [[Digital Signal 1|T1 lines]]. [[Plain old telephone service]] lines generally cannot be equipped with smartjacks.

Despite the name, most smartjacks are much more than a simple [[Telephone jack and plug|telephone jack]]. One common form for a smartjack is a [[printed circuit board]] with a face plate on one edge, mounted in an enclosure.

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== Optical network terminals ==

[[File:Tellabs ONT611 inside.jpeg|thumb|An optical network terminal mounted to the outside of a building, with the cover open]]

In fiber-to-the-premises systems, the signal is transmitted to the customer premises using [[optical fiber]] technologies. Unlike many conventional telephone technologies, this does not provide power for premises equipment, nor is it suitable for direct connection to customer equipment. An '''optical network terminal''' ('''ONT''', an [[ITU-T]] term), also known as an '''optical network unit''' ('''ONU''', an [[Institute of Electrical and Electronics Engineers|IEEE]] term), is used to terminate the optical fiber line, [[multiplexing|demultiplex]] the signal into its component parts (voice [[telephone]], [[television]], and [[Internet access]]), and provide power to customer telephones. If the device combines all these services into one it is known as an [[Integrated access device|IAD]]. As the ONT must derive its power from the customer premises electrical supply, many ONTs have the option for a [[Electric battery|battery]] backup in order to maintain service in the event of a [[power outage]] or it will go in alarm mode if disconnected and customer may be notified of this.<ref name="whatont" /> These terminals are used in both [[Fiber to the x#Active optical network|active optical networks]] and [[passive optical network]]s. Typically, an ONT connects via a fiber-optic cable to an [[Optical line termination|OLT]] to complete a connection. An ONT can work in Single Family Unit/SFU mode (modem/bridge) or Home Gateway Unit/HGU mode (router). In [[passive optical network|passive optical networks]], Management is provided by the OLT via OMCI, in case of a [[GPON]] connection, and OAM in case of a EPON connection. Authentication and encryption is done via LOID for EPON and PLOAM password, GPON serial number or others for [[GPON]].

== Environmental conditions ==

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* [[CSU/DSU]]

* [[Customer-premises equipment]]

* [[Data circuit-terminating equipment]]

* [[On-premises wiring]]

* [[Data service unit]]

* [[GPON]]

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* [[Main distribution frame]]

* [[Network termination]]

* [[On-premises wiring]]

* [[Optical modem]]

* [[Optical line termination]]