Network interface device

In telecommunication, the term network interface device (NID, network interface unit) has the following meanings:

• 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.

Source: from Federal Standard 1037C