Main Page | See live article | Alphabetical index Network termination 1 (NT1): In Integrated Services Digital Networks (ISDN), a functional grouping of customer-premises equipment that includes functions that may be regarded as belonging to OSI Layer 1, i.e., functions associated with ISDN electrical and physical terminations on the user premises. Note: The NT1 forms a boundary to the network and may be controlled by the provider of the ISDN services. Source: from Federal Standard 1037C This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.