N(s) : Send Sequence Number [Communications]

N-ISDN : Narrow Band ISDN [Communications]

N/A : not applicable

NAB : National Association of Broadcasters [Communications]

NACC : North American Calibration Cooperation

NACCB : National Accreditation Council for Certification Bodies - UK

NACE : National Association of Corrosion Engineers - USA

NACLA : National Cooperation for Laboratory Accreditation - USA

NACQS : Comité National pour l'Accéditation des Organismes de Certification

NADC : North American Digital Cellular [Communications]

NADCAP : National Aerospace and Defense Contract Accreditation Program - USA

NADH : North American Digital Hierarchy [Communications]

NAFTA : North American Free Trade Agreement

NAMAS : National Measurement Accreditation Service - UK

NAME : National Association of Metrologists and Engineers - USA

NAMPS : Narrowband Advanced Mobile Phone Service [Communications]

NANP : North America Numbering Plan [Communications]

NAPTO : National Accreditation Program for Testing Organizations - USA

NAQSIRO : North American Quality System Registration Organization - USA

NAS : Norske Akkrediterrings-System. (Norwegian Accreditation System)

NASA : National Aeronautics and Space Administration - USA

NAT : Network Address Translation [Communications]

NATA : National Association of Testing Authorities - Australia

NATLAS : National Testing Laboratory Accreditation Scheme

NATO : North Atlantic Treaty Organization

NATO : North Atlantic Treaty Organization [Military]

NAVICP : Naval Inventory Control Point  [Military]

NAVSEA : Naval Sea Systems Command

NAVSUP : Naval Supply Systems Command  [Military]

NBC : nuclear, biological, and chemical [Military]

NBS : National Bureau of Standards (now NIST) - USA

NBSM : Nepal Bureau of Standards and Metrology

NC : Network Channel [Communications]

NCA TSC : Non-Call Associated Temporary Signaling Connection [Communications]

NCAR : National Center for Atmospheric Research - USA

NCB : national certification body

NCCLS : National Committee for Clinical Laboratory Standards - USA

NCI : Network Channel Interface [Communications]

NCM : National Centre of Metrology - Bulgaria

NCO : Numerically-controlled oscillator [Communications]

NCP : Network Control Point [Communications]

NCR : no calibration required

NCS : National Calibration Service - South Africa

NCSCI : National Center for Standards and Certification Information (NIST) - USA

NCSL : National Conference of Standards Laboratories - USA

NCTE : Network Channel Terminating Equipment [Communications]

NCWM : National Conference of Weights and Measures - USA

NDE : nondestructive evaluation

NDF : New Data Flag [Communications]

NDI : nondevelopmental item  [Military]

NDT : nondestructive test

NE : Near End [Communications]

NEC : National Electrical Code - USA

NEMA : National Electrical Manufacturers' Association - USA

NEMI : National Electronics Manufacturing Initiative, Inc. [Communications]

NEMS : NASA Equipment Manufacturers' System - USA

NET : new equipment training [Military]

NETP : new equipment training plan [Military]

NEXT : Near End Crosstalk [Communications]

NF : Noise figure [Communications]

NFAS : Non-Facility Associated Signaling [Communications]

NFK : Norwegian Society for Quality

NFPA : National Fire Protection Association - USA

NFS : Network File Server [Communications]

NGDLC : Next Generation Digital Loop Carrier [Communications]

NGSB : nongovernment standards bodies

NHI3 : NASA Handbook - USA

NI : Network Interface [Communications]

NI-1 : National ISDN-1 [Communications]

NI-2 : National ISDN-2 [Communications]

NID : Network Identification [Communications]

NIHF : National Instrument Historical File  [Military]

NIM : National Institute of Metrology - China

NIOSH : National Institute of Occupational Safety and Health - USA

NIS : National Institute for Standards - Egypt

NISIT : National Institute of Standards and Industrial Technology - New Guinea

NIST : National Institute of Standards and Technology - USA

NIST : National Institute of Standards and Technology  [Military]

NIU : Network Interface Unit [Communications]

NKO : Nederlands Kalibratie Orangisatie (Netherlands Calibration Organization)

NLOC : Network Local Loopback [Communications]

NLPID : Network Level Protocol ID [Communications]

NLSP : Network-link services protocol [Communications]

NLT : not less than

NMA : Network Management and Administration [Communications]

NMC : National Metrology Centre - Vietnam

NMI : NASA Management Instruction - USA

NML : National Measurement Laboratory - Australia

NML : National Metrology Laboratory - Ireland

NMP : Network Management Protocol [Communications]

NMR (normal-mode rejection) : The ability of a panel meter to filter out noise superimposed on the signal and applied across the SIG HI to SIG LO input terminals. Normally expressed in dB at 50/60 Hz.

NMS : National Measurement Service - Norway

NMT : not more than

NMT-900 : Nordic Mobile Telephone [Communications]

NNI : Nederlands Normalisatie-Instituut (Netherlands Standardization Institute)

NOAA : National Oceanic and Atmospheric Administration - USA

NOC : Network Operations Center [Communications]

NOLA : Norwegian Testing Laboratory Accreditation System

NORDTEST : Nordic Cooperation Body for Technical Testing - Finland

NOTE : Network Office Terminating Equipment [Communications]

NPAC : Number Portability Administration Center [Communications]

NPDA : Network Problem Determination Application [Communications]

NPFC : Naval Publications and Forms Center - USA

NPI : Numbering Plan Identification [Communications]

NPL : National Physical Laboratory - UK

NPLI : National Measurement Laboratory of India

NPODS : Navy Publishing-on-Demand System - USA

NPPSO : Naval Publications and Printing Service Office - USA

NPSI : Network Packet Switching Interface [Communications]

NPSL : National Physical and Standards Laboratory - Pakistan

NPSL : Navy Primary Standards Laboratory - USA

NQAA : National Quality Assurance Authority - USA

NRC : Nuclear Regulatory Commission - USA

NRC : Nuclear Regulatory Commission [Military]

NRCC : National Research Council of Canada

NREM : Network Remote Loopback [Communications]

NRLM : National Research Laboratory of Metrology - Japan

NRRJ : Non-Repeated Route Junction [Communications]

NRT : Non-Real Time [Communications]

NRTL : National Research Testing Laboratory - USA

NRTL : nationally recognized testing laboratory

NRZ : Non-Return to Zero [Communications]

NRZI : Non-Return to Zero Inverted [Communications]

NSA : National Standards Association - USA

NSA : National Security Agency - USA

NSAI : National Standards Authority of Ireland

NSAP : Network Service Access Point [Communications]

NSC : National Standards of Canada

NSDA : National Space Development Agency - USA

NSF : Norges Standardiseringsforbund (Norwegian Standards Association)

NSF : National Science Foundation - USA

NSI : Network Service Interface [Communications]

NSLAP : Navy Shipyard Laboratory Accreditation Program

NSN : national stock number [Government] 

NSRDS : National Standard Reference Data Program - USA

NSS : National Standards System - USA

NSWC : Naval Surface Weapons Center - USA

NTE : Network Terminating Equipment [Communications]

NTEP : National Test Equipment Partnership (NIST, NCWM, state governments, and test equipment manufacturers) - USA

NTIS : National Technical Information Service - USA

NTSC : National Television Standard Code - USA

NTSC standard : Abbreviation for National Television Standards Committee standard. The North American standard (525-line interlaced raster-scanned video) for the generation, transmission, and reception of television signals.

NTTC : National Technology Transfer Center - USA

NUI : Network-to-User Interface [Communications]

NVCASE : National Voluntary Conformity Assessment System Evaluation - USA

NVLAP : National Voluntary Laboratory Accreditation Program (NIST) - USA

NVRAM : Non-Volatile Random Access Memory [Communications]

NWAC : Naval Warfare Assessment Center - USA

NWCF : Navy Working Capital Fund  [Military]

NYIIX : New York International Internet Exchange [Communications]

NZOQ : New Zealand Organization for Quality

Near-Field Region : That part of space between the antenna and the far field region.

NiCd : Nickel cadmium [Communications]

NiMH : Nickel metal hydride [Communications]

Noise : 1. An undesired disturbance within the frequency band of interest; the sum-mation of unwanted or disturbing energy introduced into a communications system from man-made and natural sources. 2. A disturbance that affects a signal and that may distort the

Noise Distortion : When circuits are driven with a broadband noise signal, the nonlinear behavior that results.

Noise Floor : (1) A cutoff point from which no appreciable information from a signal can be retrieved below. (2) The minimum discernible signal that can be detected by a receiver.

Nyquist Sampling Theorem : This theorem states that if a continuous bandwidth-limited signal contains no frequency components higher than fC, then the original signal can be recovered without distortion as long as it is sampled at a rate of at least 2 fC.