Glossary N-O0-A | B | C-Cn | Co-Cz | D | E | F-G | H-I | J-L | M | N-O | P-Q | R | S | T | U-Z
0-A | B | C-Cn | Co-Cz | D | E | F-G | H-I | J-L | M | N-O | P-Q | R | S | T | U-Z
- NA: See Numerical Aperture
- NAK: See Negative
- Name Binding Protocol: (NBP)
AppleTalk protocol for translating devices names to addresses.
- Nanometer: (nm) One billionth of a meter = 10-9
- Nanosecond: One billionth of a second.
- National Electrical Code: (NEC) which defines building
flammatory requirements for indoor cables.
Television System Committee: (NTSC) One of the standards for television
signals, developed in 1941. Has 486 visible horizontal lines.
See Name Binding Protocol
- NCC: See Network Control Center
- NDIS: See Network Driver Interface Specification
- Near End Crosstalk: (NEXT) Crosstalk measured at the end
from which the disturbing signal is transmitted.
- NEC: See National Electrical Code
Acknowledgment: (NAK) A data link control character transmitted by the
receiver as a negative response to the sender. The response may relate to data
or control information.
- NEMA: National Electrical Manufacturers
- Neoprene: A synthetic rubber with good resistance to
oil, chemical, & flame. Also called polychloroprene.
- Net Id: See Network Identification
- NetBIOS: See Network Basic Input/Output System
- Netview: An IBM
mainframe network management product that integrated the function of several
earlier IBM network management products.
- NetWare: Novell's network
operating system using IPX (Internetwork Packet Exchange) & SPX (Sequential
Packet Exchange) protocols.
- Network: A set of communication channels
inter-connecting several devices and/or locations.
Architecture: A description of data formats & procedures used for
communication between nodes.
- Network Basic
Input/Output System: (NetBIOS) A widely-used protocol governing data
exchange & network access.
- Network Control Center:
(NCC) Any centralized network diagnostic & management station or site, such as
that of a packet-switching network.
- Network Driver
Interface Specification: (NDIS) Specification for a generic device driver
for network interface cards that are independent of hardware &
- Network File System: (NFS) Sun
Microsystems' network operating system based on TCP/IP protocols.
- Network Identification: (Net Id) The first part of the
32-bit IP address.
- Network Information Frame:
(NIF) determines which FDDI station is upstream & which is downstream when two
stations are talking.
- Network Interface Card: See Network Interface Controller
Interface Controller: (NIC) Electronic circuitry that connects a
workstation to a network, usually a card that fits into one of the expansion
slots inside a personal computer. It works with the network software & computer
operating system to transmit & receive messages on the network.
Interface Module: See Adapter
- Network Layer: Layer 3 of the OSI (Open Systems
Interconnection) model; it defines protocols governing data routing.
- Network Loadable Module: (NLM) An application or driver
that resides on a NetWare server to provide additional resource management
- Network Management System: (NMS)
Systems equipment used in monitoring, controlling & managing a data
- Network Operating Systems:
(NOS) Software that provides users with a variety of data communication service
including file sharing, electronic mail, security systems & methods for
connecting network systems.
- Network Topology: The arrangement of
nodes usually forming a star, ring, tree, or bus pattern.
- NEXT: See
Near End Crosstalk
- NFS: See Network File System
- NIC: See Network
- NIF: See Network Information
- NIM: (Network Interface Module) See Adapter Card
- NLM: See Network Loadable Module
- NM: See Nanometer
- NMS: See Network
- Nodes: A device connected to the network which
can be addressed by other nodes.
- Noise: In a cable or circuit, any
extraneous signal which tends to interfere with the signal normally present in
or passing through the system.
- Non-Return to Zero:
(NRZ) Binary coding transmission with no return to neutral state after each bit
- Nondedicated server: A node on which user
applications are available while network resources maintenance applications
execute in the background.
- NOS: See Network Operating
- NRZ: See Non-Return to
- NTSC: See National Television System
- Null Modem: A device that connects two DTE's directly
by emulating the physical connections of a DCE.
- Numerical Aperture: (NA) A measure of the angular
acceptance for a fiber. It is approximately the sine of the half angle of the
- Nylon: An abrasion-resistant thermoplastic with good
- ODI: See Open Datalink
- Ohm: The electrical unit of resistance. The value of
resistance through which a potential difference of one volt will maintain a
current of one ampere.
- Open Datalink Interface:
(ODI) a standard interface specification developed by Novell to enable PC
adapter cards to run multiple protocol stacks.
Shortest Path First: (OSPF) A distribution algorithm & routing protocol
used by routers to compute the best path to be used to forward packets through
an internetwork. It is derived from the OSI Shortest Path First (SPF)
- Open System: A networked computer or software which can
easily be extended or enhanced with precuts from another vendor or technology
source. Open systems usually imply the use of standard, replaceable protocols &
hardware components, & well-defined interfaces.
Systems Interconnection: (OSI). A standard developed by the ISO
(International Standards Organization) for a logical network operations
- Operating System: A program which controls the operation,
scheduling & various other related functions of other programs within the
- Optical Disk: A very high-density information storage
medium that uses light to read & write digital information.
- Optical Fiber
Cable: An assembly consisting of one or more optical fibers (glass or
plastic) with strengthening material & an outer jacket.
- Optical Fiber
Duplex Connection: A mated assembly of two duplex connectors & a duplex
- Optical Fiber Duplex Connector: A mechanical media
termination device designed to transfer optical power between two pairs of
- Optical Time Domain Reflection: An instrument that
measures transmission characteristics of fiber by sending a pulse of light down
the fiber & measuring the light scattered across the length & reflected back
from the end as a function of time.
- OS/2: The third generation
operating system developed by IBM & Microsoft for use with the Intel 80286 &
80386 microprocessors. Unlike its predecessor (PC MS-DOS), OS/2 is a
multitasking operating software that will run on the Personal System/2. OS/2
Standard Edition is a joint Microsoft & IBM development, while OS/2 Extended
Edition is the IBM proprietary extension to include communications & database
- OSI: See Open Systems
- OSINET: A test network, sponsored by the National
Bureau of Standards (NBS), designed to provide vendors of products based on the
OSI model a forum for inter-operability testing.
- OSPF: See Open Shortest Path First
- Overhead: In
communications, all information, such as control, routing, & error-checking
characters, that is in addition to user transmitted data; includes information
that carries network status or operational instructions, network routing
information, & retransmission of user data messages that are received in
- Ozone: Extremely reactive form of oxygen, normally occurring
around electrical discharges & present in the atmosphere in small but active
quantities. In sufficient concentrations it can break down certain rubber
insulation's under tension (such as a bent cable).