Network Termination 1 (NT1) or Network Termination type 1 refers to equipment in an

Integrated Services Digital Network Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Work ...

(ISDN) that physically and electrically terminates the network at the customer's premises. The NT1 network termination provides signal conversion and timing functions which correspond to layer 1 of the

OSI model The Open Systems Interconnection model (OSI model) is a conceptual model that 'provides a common basis for the coordination of SOstandards development for the purpose of systems interconnection'. In the OSI reference model, the communications ...

. In a

Basic Rate Interface Basic Rate Interface (BRI, 2B+D, 2B1D) or Basic Rate Access is an Integrated Services Digital Network (ISDN) configuration intended primarily for use in subscriber lines similar to those that have long been used for voice-grade telephone servi ...

, the NT1 connects to line termination (LT) equipment in the provider's telephone exchange via the

local loop In telephony, the local loop (also referred to as the local tail, subscriber line, or in the aggregate as the last mile) is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the commo ...

two wire

U interface U or u, is the twenty-first and sixth-to-last letter and fifth vowel letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''u'' (pr ...

and to customer equipment via the four wire S interface or T interface. 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 In telecommunications, a customer-premises equipment or customer-provided equipment (CPE) is any terminal and associated equipment located at a subscriber's premises and connected with a carrier's telecommunication circuit at the demarcation po ...

(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.

References

Integrated Services Digital Network {{telecomm-stub