In telecommunications, the term 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 a loop-back device[1][2] that serves as the point of demarcation between the end user's inside wiring and local access carriers' facilities. These devices are commonly located in the basement, first floor telco room, garage, or even outside the building in weatherproof enclosures, but can be located anywhere the LEC wishes to place it. NIUs are multi-functional devices, which include a protector block to prevent high-voltage surges from affecting premise equipment and inside wiring.
- NIUs are loopable devices used by LECs to test the local loop and isolate problems, allowing the LEC to run paterns to the front of the smartjack. When the CSU is no longer avaliable the NIU is designed to send an AIS alarm back to the LECs CO.
- A device that performs interface functions, such as code conversion, protocol conversion, and buffering, required for communications to and from a network.
- A device used primarily within a local area network (LAN) to allow a number of independent devices, with varying protocols, to communicate with each other.
An NID converts each device protocol into a common transmission protocol.
The transmission protocol may be chosen to accommodate directly a number of the devices used within the network without the need for protocol conversion for those devices by the NID.
Common practice
The NIU belongs to the PSTN provider. Together with the CSU it represents the PSTN demarcation point. The CSU is the first piece of Customer Premise Equipment (CPE). If the NIU fails the PSTN provider is responsible for repairs; if the CSU fails the customer is responsible for repairs.
References
- ^ "T1/E1 Bit Error Rate Testing". GL Communications. Retrieved 2008-02-09.
- ^ "3125 Series T1 Network Interface Unit Stat Sheet". Westell. Retrieved 2008-02-09.