Network Termination 1 (NT1) or Network Termination type 1 refers to equipment in an Integrated Services Digital Network (ISDN) that physically and electrically terminates the network at the customer's premises.[1][2] The NT1 network termination provides signal conversion and timing functions which correspond to layer 1 of the OSI model.[2] In a Basic Rate Interface, the NT1 connects to line termination (LT) equipment in the provider's telephone exchange via the local loop two wire U interface and to customer equipment via the four wire S interface or T interface.[2] The S and T interfaces are electrically equivalent, and the customer equipment port of a NT1 is often labelled as S/T interface. There are many types of NT1 available.
In the United States, the NT1 is considered customer-premises equipment (CPE) and is as such generally provided by the customer or integrated into the customer's equipment. In this case, the U interface is the termination point of the ISDN network. In Europe, the NT1 is generally provided by the provider, and the S/T is the termination point of the ISDN network.[3]
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This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 2022-01-22.
- ^ a b c Steve Winder (9 October 2001). Newnes Telecommunications Pocket Book. Newnes. pp. 83–85. ISBN 978-0-08-049748-8.
- ^ Becker, Ralph (2006-12-05). "ISDN Tutorial: Interfaces". ralphb.net. Retrieved 2014-01-22.
