N-ISDN (Narrowband Integrated Services Digital Network). Services include basic rate interface (2B+D or BRI) and primary rate interface (30B+D - Europe and 23B+D - North America or PRI). It supports narrowband speeds at/or below 1.5 Mbps.

NADC (North American Digital Cellular standard). NADC is one of a number of second generation digital cellular standards used in North America. It is specified by the IS-54 standard. NADC offers three times the capacity of the original analog AMPS system.

Narrowband. A communications path that carries data at a speed of 56 kbps or less.

Narrowband network. A network capable of carrying data at a speed of 64 kpbs. The telephone network is a narrow band network.

Network. The connection between multiple infrastructure equipment sites for the reception and possible transmission of information.

Network architecture. The infrastructure equipment that makes up a network and the way it is arranged.

Network device. Any communications equipment attached to a network.

Network layer. The third layer of the OSI model which is concerned with the routing and switching of data from its source to its destination.

Network operator. A service provider for subscribers.

Network security. Software and hardware used on a network to restrict access to users of the network.

NIT (Network Information Table). A DVB/MPEG-2 PSI table that contains data about the network.

NIT (Network Information Table). A DVB/MPEG-2 PSI table that contains data about the network.

NMT (Nordic Mobile Telephony). An analog standard for mobile systems, which was developed by the Scandinavian Telecommunication Administrations.

NNI (Network Node Interface). An interface between ATM switches defined as the interface between two network nodes.

Node. A generic name for a single functional entity on a network, such as an MSC, BSC, HLR GMSC, VLR, or a BTS.

Nonvolatile. A term used to describe a device that retains its memory contents while it is powered off.

Nonwireline. Any cellular service provider other than the local PSTN.

Noise. Unwanted signal degradation in communications systems. It can have many causes.

NPA (Numbering Plan Area). Area codes for a country.

NPA routing. Numbering Plan Area routing. The routing of calls according to their area code.

Network And Switching Subsystem (NSS). A subsystem comprised of the MSC, GMSC, HLR, VLR, AuC, and EIR,

NTT (Nippon Telephone and Telegraph). The principal common carrier in Japan. The Japanese equivalent of AT&T in the U.S.