Network termination 1
Encyclopedia
Network Termination 1: 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.
The physical equipment is also known as a terminal adapter
.
In the United states the customer usually has to provide the NT1, whereas in other countries it is usually the carrier company that provides it.
The interface from the NT1 to the telephone exchange
is the U interface
. Customer equipment commons connects via an S bus but may also use USB, or a serial port
.
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
Networks (ISDN
Integrated Services Digital Network
Integrated Services Digital Network is a set of communications standards for simultaneous digital transmission of voice, video, data, and other network services over the traditional circuits of the public switched telephone network...
), a functional grouping of customer-premises equipment
Customer-premises equipment
Customer-premises equipment or customer-provided equipment is any terminal and associated equipment located at a subscriber's premises and connected with a carrier's telecommunication channel at the demarcation point...
that includes functions that may be regarded as belonging to OSI Layer
Layer
Layer may refer to:* A layer of archaeological deposits in an excavation* A layer hen, a hen raised to produce eggs* Stratum, a layer of rock or soil with internally consistent characteristics...
1, i.e., functions associated with ISDN electrical and physical terminations on the user
User (telecommunications)
In telecommunications, a user is a person, organization, or other entity that employs the services provided by a telecommunication system, or by an information processing system, for transfer of information....
premises.
Note: The NT1 forms a boundary to the network
Telecommunications network
A telecommunications network is a collection of terminals, links and nodes which connect together to enable telecommunication between users of the terminals. Networks may use circuit switching or message switching. Each terminal in the network must have a unique address so messages or connections...
and may be controlled by the provider of the ISDN services.
The physical equipment is also known as a terminal adapter
Terminal adapter
- ISDN :In ISDN terminology, a terminal adapter or TA is a device that connects a terminal to the ISDN network.The TA therefore fulfills a similar function to the ones a modem has on the POTS network, and is therefore sometimes called an ISDN modem...
.
In the United states the customer usually has to provide the NT1, whereas in other countries it is usually the carrier company that provides it.
The interface from the NT1 to the telephone exchange
Telephone exchange
In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls...
is the U interface
U interface
U interface: For basic-rate access in an Integrated Services Digital Network environment, a user-to-network interface reference point that is characterized by the use of a 2-wire-loop transmission system that conveys information between the 4-wire user-to-network interface, i.e., the S/T...
. Customer equipment commons connects via an S bus but may also use USB, or a serial port
Serial port
In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time...
.