EE Terminology

N or N type: See cable connector.
n00b: Noob, from “new boy”, i.e., a novice. The worst possible insult among the l337.
NAC: Network Admission Control. Security software, originated by Cisco, that checks the software of equipment attempting to access a network, and blocks unsafe or compromised systems. Most versions require the accessing system to download an agent.
NACS: North American Charging Standard. See EV.
NAMPS: Narrowband Advanced Mobile Phone System. Obsolete mobile technology to combine cellular voice processing with digital signaling, increasing the capacity of AMPS and adding functionality.
NAND: Not And. See binary logic, flash memory.
nanotube: Usually means a carbon nanotube (CNT), formed from a 1-atom thick sheet of graphene rolled into a tube. There are 400 different types, distinguished by the tube’s diameter and chirality (the orientation of the honeycomb pattern with respect to its axis). These determine the tube’s electrical properties, notably its band gap. The nanotube is expected to be the basis for a new generation of ultra-tiny semiconductor devices and ultra-strong materials. The chief hurdle is consistency in manufacture.
NAP: Network Access Point. (Obsolete) Any of the four US sites at which ISPs connected to the early Internet.
NAS: (1); Network-Attached Storage. A data-storage unit connected directly to a network instead of to an individual computer. Its storage medium, whether hard disk drive or SSD, is commonly optimized for frequent data writes rather than for speed. It’s also called a surveillance drive because a common use is storing video from security cameras. It provides slightly slower access than a conventional HDD, but is more tolerant of heat and vibration to stand up to constant operation. Not the same thing as a SAN.; (2); Network Access Server. A server that acts as the gateway for outside access to a network. See VPN.
NASA: National Aeronautics and Space Administration.
NAT: Network Address Translation. Also called masquerading. A technology that uses valid, public IPv4 addresses to dynamically present a larger set of private subnet addresses as if each were a unique Internet server. This complicated illusion permits a subnet to have more public servers than it has public addresses. Reliance on NAT is variously considered a crucial patch to support full rollout of IPv6, or a band-aid that’s holding back IPv6, with the latter view gaining ground.; A router or firewall that manages NAT is also called a NAT-PT (NAT Protocol Translator). Newer versions exploit unallocated TCP/IP port numbers, an approach dubbed network address and port translation (NAPT) or port address translation (PAT). Carrier-grade NAT (CGN, or CGNAT) refers to ISPs using NAT to support Internet servers run by their customers.
NBAN: Next-generation Broadband Access Network. A planned replacement for the current DOCSIS cable-modem network. It uses a broadband interface unit (BIU) to tie the subscriber’s LAN to the provider’s coaxial cable, and an optical network distribution switch (ONDS) to connect the NBAN to the trunk line of the provider’s WAN.
N.C. (NC, N/C): (1); Normally Closed. In wiring diagrams, a switched line that’s closed when the system is in its normal state, tying the line to a common reference. A specific event will open the switch. Compare N.O.; (2); Not Connected. In circuit diagrams, indicates that a pin or wire is not connected to anything.
NCD: NanoChromics Display. A ~2005 flat-panel display technology with higher contrast, lower power draw, and lower cost than the similar LCD, but also much lower speed. Rather than using an electric field to orient liquid crystals to block or admit light, a NCD applies the field to charge electrochromic materials coating the front screen of the display, changing their color from transparent to something else. Used for electronic paper and labels.
N-CDMA: Narrowband CDMA. See CDMA.
NCO: Numerically Controlled Oscillator. A device that produces a variable analog output frequency in response to a digital input.
NCP: Network Control Program. ARPANet protocol used at the Transport layer of the network, discarded in the 1983 shift to TCP/IP.
NCR: Numeric Character Reference. A character representation notation in HTML for characters outside the basic ASCII set. It begins with an ampersand-pound escape sequence, and terminates with a semicolon. For example, the sequences ¥ (decimal) and ¥ (hexadecimal) both direct a browser to display ¥, the Yen symbol, which is Unicode decimal value 165.
NCSA: National Center for Supercomputing Applications. A computing research center at the University of Illinois (http://www.ncsa.illinois.edu), established in 1986 by the NSF. Creators of Mosaic, the first Web browser.
NDA: Non-Disclosure Agreement.
NDI: Nexus Debug Interface. See Nexus.
NDIS: Network Driver Interface Specification.
NDP: Neighbor Discovery Protocol. Part of the TCP/IP protocol suite at the Link layer (the Data link layer of the OSI model).
NDSF: Non-zero Dispersion Shifted Fiber. A type of optical fiber that can handle the increasing numbers of channels used by the newer WDM signals.
Nd:YAG: Neodymium Yttrium Aluminum Garnet. See YAG.
near field: The area within one wavelength of an EM wave’s source, where different rules apply. See near field communication.
NEC: (1); National Electrical Code. An ANSI-supported safety standard for US commercial and residential electrical circuits & wiring, updated every 3 years by the National Fire Prevention Agency (NFPA) as ANSI/NFPA 70. It incorporates the NEMA standards for AC power sockets and plugs.; (2); Nippon Electronics Corporation. A big Japanese manufacturer of computer hardware and electronics, now part of Renesas, the company formed by the merger of Mitsubishi and Hitachi.
NEMA: National Electrical Manufacturers Association. A US standards body for electrical equipment, best known for WD 6, its standards for AC power sockets and plugs.; The WD 6 naming convention uses the form (L)#-##X. A leading “L” indicates a locking rather than a straight-blade connector. The first number, the configuration, indicates the voltage level(s) and wiring; the second number is the amperage; and the final letter is either “P” for plug, “R” for receptacle, or “C” for connector. The current standard’s configurations are:; For example, in the US, the basic residential AC power socket is the 5-15R: 125-volt, single-phase, 2-pole, 3-wire, grounding, 15 amps, receptacle. The other 125-volt outlets, including the locking types, are also common. Three-phase and high-voltage connectors are for equipment with exceptional power demands. Non-grounding outlets are considered unsafe and have largely disappeared, although non-grounding plugs remain common. The figures below show some of these sockets, to a consistent scale.; By design, plugs physically mate only with receptacles and connectors rated for the same voltage and the same or greater current. Although the standard doesn’t specify, it’s become common, for safety reasons, to install outlets with the ground hole at the top. The chief objection to this practice is that the socket won’t look like a little surprised face.; The grounding wire – “G” in the figures – should be bare or, if insulated, green or green & yellow. The neutral or grounded (not grounding) wire, “W”, which is bonded to the return path at only one point, is gray or white. The hot wire, “X”, is black. If there are multiple hot lines, the others are “Y” and “Z”.; In addition to the numerical configurations mentioned above, the NEMA standard has a few oddballs, including at least one DC connector. Gory details are at http://www.nema.org/stds/wd6.cfm.
NEMS: Nano-Electromechanical System. Like MEMS, only smaller.
NEO: Near-Earth Object. An asteroid or comet that passes close enough to Earth’s orbital path to be of concern. Astronomers have identified thousands of them, but the total number is thought to be in the millions, with an estimated 1,000 having dimensions larger than 1 km. The dinosaur-killing asteroid that created the Chicxulub crater 66 million years ago was about 10 km in diameter.
.NET: Pronounced “dot net”. Microsoft’s Common Language Runtime (CLR) – the environment within which .NET programs run – plus a huge, hierarchical set of class libraries containing everything that Microsoft thinks developers will ever need for network-aware programming.; .NET-compliant managed code doesn’t initially compile into a platform-specific executable, but into three sections – an Intermediate Language (IL) executable, the metadata, and the manifest – all in a Portable Executable (PE) wrapper. (PE is the Win32 binary file format.) At run time, the CLR uses just-in-time compiling to convert the assembly-like IL into platform-specific code. The metadata describes the contents of the file, including input and output. The manifest identifies components the executable needs, and provides public keys so the CLR can verify these components. Compare J2EE, Java.
NetBEUI: NetBIOS Extended User Interface. A device driver and transport protocol originated by IBM (1985) for sharing hardware over small networks. It can bind with up to eight MAC drivers.
NetBIOS: Network Basic Input/Output System. An extension of IBM’s PC BIOS, developed as the interface for the PC Network program.
netbook: A portable computer smaller and cheaper than a notebook PC, optimized for Internet browsing at the cost of processing power and other features. It lost out at both ends of its market to smart phones and notebook PCs. The more expensive and fragile tablet computer has been more successful, because it offers touchscreen interface, smaller size, and – most important – built-in wireless connectivity.
netlist: A list of symbols or parts in a circuit, with information about how they’re laid out and connected. It’s used in creating PCBs and PLD programs. A netlist can be captured from schematic drawing files. File formats for a netlist include the generic EDIF as well as proprietary standards for common HDLs.
netmask: A number in the same format as an IP address, used for routing purposes to identify the network the IP address is on. For IPv4, it’s four integers between 0 and 255 inclusive separated by periods, e.g., 255.240.0.0. It’s sometimes represented in hexadecimal form, e.g., 0xFFF00000.; A bitwise AND of an IP address with the netmask of the device at that address yields the address of the device’s network. If a device has IP address 192.72.144.8 and netmask 255.240.0.0, the network address is [192.72.144.8 AND 255.240.0.0] = 192.64.0.0. When a device is sending to another device on the same network, it can send directly. When sending to a different network, it needs to consult a routing table to identify a server that can forward the message.
NetWare: Novell’s network OS (NOS), which isolates platform dependencies in the node that runs the NetWare kernel. It peaked in the 1990s, and is now just a niche player in the networking world.
network analyzer: “Network” here refers to an electrical circuit, not a communications network. A circuit in this sense can be as simple as a single component with one input and one output. The scalar network analyzer (SNA), which is very similar to a spectrum analyzer, measures and analyzes changing voltage amplitudes at nodes on a circuit. The more sophisticated vector network analyzer (VNA) can also analyze voltage phase. See S-parameters.
network processor: A CPU chip optimized for handling network data packets. New concept (2001).
neural network: See ANN.
newton: Named for English scientist & mathematician Isaac Newton (1642-1727). The SI standard unit of force, sufficient to accelerate a 1-kg mass by 1 m/s². Hence, 1 N = 1 kg-m/s².
NexGen: A chip maker that AMD bought in 1996 to get the Nx686 processor design, which became the K6.
NEXT: Near-End Crosstalk. Usually results from high-frequency signals, unbalanced lines, and lack of shielding. See crosstalk.
Nexus: Also called the Nexus debug interface (NDI). An IEEE standard interface for testing & debugging embedded systems, defined by the Nexus 5001 Forum and initially released as IEEE ISTO 5001-1999. The forum issued revisions in 2003 and in 2011.; Run-control debugging standards such as JTAG and BDM rely on the processor using external memory. However, it has become common for microprocessors and microcontrollers to have internal memory. Nexus supports on-chip memory access and real-time debugging, i.e., without stopping the processor. It can use any of several standard protocols and physical ports, including JTAG.; Nexus is meant to provide flexibility to system designers. It defines four implementation classes, each offering more features and more detailed control than the last, but designers do not have to conform to a class. It also has this basic set of signal lines, although an implementation can have others:
NFC: Near Field Communication. A type of communication originally used for passive RFID but now finding other applications. Rather than broadcasting RF with an antenna, it uses an inductor coil to emit just the modulated magnetic component of the near field. This requires less power than an RF system with similar data rates. The range is very short, but this can be a security advantage, and it allows for unpowered receivers that draw operating power inductively from the signal field.; NFC is also the name of an ISO open standard for smartphones to exchange information directly with one another or with NFC-equipped terminals, without going through a network. For security and privacy as well as battery conservation, range is 20 centimeters or less. It uses a 13.56 MHz carrier, ASK modulation, Manchester or NRZ-L encoding, and half-duplex 106, 212, or 424 kb/s data rate. It sends the data in variable-length asynchronous frames, each consisting of an all-zero preamble at least 48 bits long, 16-bit sync word 0xB24D, 8-bit payload length, 3- to 255-byte payload, and 16-bit CRC. The first two bytes of each payload must be a command chosen from the standard’s NFCIP-1 protocol set.
NFMI: Near Field Magnetic Induction. A more specific name for NFC.
NFS: Network File System. A member of the TCP/IP protocol suite at the Application layer, created in 1984 by Sun Microsystems. Mainly for Unix and related operating systems, it enables users to access shared files across a network.
NFT: Non-Fungible Token. A blockchain-backed virtual object that conveys ownership of something intangible. For example, an artist could sell a digital image of an artwork as a NFT. Its purchaser wouldn’t have any rights to the original artwork, or even to other images of it. The question of what rights, if any, it does convey has yet (2022) to face any serious legal test.; Just as with cryptocurrency or, indeed, fiat currency, a NFT’s value depends on what other people think it’s worth. However, unlike fiat currencies, NFTs and cryptocurrencies are commonly viewed as speculative investments. That ensures volatility and attracts scammers. See Web3.
NGFF: Next Generation Form Factor. Another name for M.2.
NHRP: Next Hop Resolution Protocol.
NI: (1); Non-Interlaced. Interlacing is an obsolete video monitor feature that skips every other line of pixels, yielding faster screen refresh rates and a dim, flickering image. NI monitors are now standard.; (2); National Instruments. A major US electronics company. Products include DAQ, LabVIEW, and a wide range of RF and electrical measurement instruments.
NIC: Network Interface Card. An expansion card to provide a network connection for a computer. Network capability has become a standard feature of PC motherboards, making the discrete NIC rare in personal computers. NICs persist in other platform types. The term is sometimes used to mean an integrated network module.
NiCd: Nickel-Cadmium. See battery.
NiMH: Nickel-Metal-Hydride. See battery.
NIR: (1); Near Infra-red. See IR (1).; (2); Non-Ionizing Radiation. See IR (2).
NIST: National Institute of Standards and Technology. At www.nist.gov. Formerly the National Bureau of Standards.
NIU: Network Interface Unit. See HFC.
NIX-1: Numerical Indicator Experimental 1. Also called “Nixie”. A glass tube containing neon and a stacked set of diodes with numeral-shaped cathodes. Applying a voltage to a diode ionizes the neon around the cathode, producing a glowing numeral. From 1954 until the 1970s, this now-obsolete device was used for numerical displays.
NLM: NetWare Loadable Module. A program that runs on a NetWare-based LAN.
NLOS: Non-Line-of-Sight. Communication links in which the transmitting and receiving antennas need not be visible to one another. Also, a wireless broadband technology for connecting subscribers to the Internet. Subscribers can have indoor and non-directional antennas, because the base station can characterize and actually exploit multi-path delays and fades using intelligent directional transmission. It also has tricks such as advanced modulation (commonly OFDM), and mesh architectures that put customer nodes to work as local routers. All of this is absolutely dependent on cheap, powerful DSP. Compare with LOS.
NLP: Natural Language Processing. Refers to computer analysis of human language, whether spoken or written, using various forms of AI.
NMEA: National Marine Electronics Association.
NMI: Non-Maskable Interrupt. An external interrupt request that software running on the processor can’t prevent, as opposed to a maskable interrupt, which software can decline to service.
NMOS: N-channel Metal-Oxide-Semiconductor. A semiconductor IC based on n-channel MOSFETs, so that the basic conduction mechanism is governed by electrons rather than holes. Compare PMOS. See also CMOS, transistor.
NMR: Nuclear Magnetic Resonance. The phenomenon exploited by MRI machines. Contrast NQR.
NMT: Nordic Mobile Telephone, or Nordisk MobilTelefoni. An analog cellular system with FM and FDMA signaling. NMT-450 had 200 channels with 25 kHz channel spacing. Its receiving channels were at 463-468 MHz, and transmitting channels at 453-458 MHz. NMT-900 offered 1999 channels with 12.5 kHz channel spacing. It had receiving channels at 935-960 MHz, and transmitting channels at 890-915 MHz.; NMT’s superior range enabled it to survive digital 2G competition for years in thinly populated regions of Iceland and Scandinavia. Those providers dropped it during 2007-2010.
NNTP: Network News Transport (or Transfer) Protocol. The protocol that connects Usenet sites to the Internet, using TCP. See TCP/IP.
N.O. (NO, N/O): Normally Open. In wiring diagrams, a switched line that’s open when the system is in its normal state. A specific event will close the switch, tying the line to a common reference. Compare N.C..
NOC: Network Operations Center.
Node.js: A popular open-source development environment & runtime environment for JavaScript.
non-coherent detection: Meaning a receiver demodulates a signal without measuring carrier phase, acting purely as an energy detector. Less complex and more error-prone than coherent detection.
NOP: No Operation. A low-level (assembler) instruction to a processor to do nothing for one clock cycle. Used for timing.
NOR: Not Or. See binary logic, flash memory.
NORAD: North American Aerospace Defense Command. US-Canadian military organization that guards North American airspace.
northbridge: Named for being at the top of motherboard circuit diagrams, corresponding to north on a map. Introduced in 1991 with the Intel Hub Architecture, this part of the PC motherboard chipset connects the CPU to main memory and to the subordinate southbridge. It links to the CPU via the front side bus. If the board has integrated graphics, that’s also here.; The Platform Controller Hub (PCH) has replaced the Hub Architecture.
NOS: Network Operating System. Working in conjunction with an OS, the NOS provides a user interface to the LAN, communicates with LAN hardware, and controls network operation. Common ones are MS Windows Server, Mac OS X Server, and versions of Unix and Linux.
NOVRAM: Same thing as NVRAM.
NP: Non-deterministic Polynomial-time. In computer science, to say that a problem has a polynomial-time solution means that the time t a computer requires to solve it scales with data input length n by some constant exponential C, hence, t = n^C. Once C is known, solution time can be accurately predicted for any practical input length. Problems for which this relation holds are called class P.; NP problems are those whose solutions can be verified in polynomial time, whether or not they can be solved there. It has been proved that any problem with a polynomial-time solution must also be verifiable in polynomial time, so any P problem is also NP.; Whether the reverse is also true – whether any problem verifiable in polynomial time must also have a polynomial-time solution, meaning NP and P are the same – is a major unsolved question. There is strong consensus that P ≠ NP, but consensus isn’t proof. A Nobel prize awaits whoever can prove or disprove it.; NP-hard problems are those with no known polynomial-time solution. NP-complete problems are NP problems that are also NP-hard – i.e., they’re verifiable but apparently not solvable in polynomial time.
NPE: Non-Practicing Entity. Also called a patent-assertion entity (PAE), or, more commonly, a patent troll: a company whose sole or primary business is licensing, litigation, litigation threats, and out-of-court settlements for questionable patents on things they don’t make. They typically choose their victims with care, and ensure that it’s cheaper for victims to settle than to contest the patent. See www.uspto.gov/patents/litigation, and also www.eff.org/issues/stupid-patent-month.
NPN: Negative Positive Negative. One of two semiconductor doping profiles for bipolar junction transistors. PNP is the other.
NPU: Neural Processing Unit. A co-processor that’s designed to run AI tasks more efficiently than a general-purpose CPU or GPU. In the so-called AI PCs introduced in 2023, it’s integrated into the CPU.
NQR: Nuclear Quadrupole Resonance. The emission of RF energy by the nuclei of elements with charge moment (non-uniform distribution of positive charge) as the charge distribution changes in response to absorption of RF. The frequency bands of the emitted energy can be used to identify the compound of which the element is a part – a form of spectroscopy. Conversely, each element is sensitive to irradiation in a distinct RF range. Only solids can exhibit NQR, not liquids or gases. Contrast NMR.
NRAM: Nano-Random Access Memory. A non-volatile RAM based on carbon nanotubes. Compared to NAND-gate flash, which it aims to replace, it’s much faster, denser, and more robust. Because of this huge speed advantage, manufacturers intend to design products that connect it to main memory buses (starting with DDR4) rather than the relatively slow storage buses such as SATA, which will mean much, much faster SSDs. NRAM is still in testing as of 2015.
NRE: Non-Recurring Engineering. Refers to one-time costs of developing a system, distinct from production costs.
NREL: National Renewable Energy Laboratory. US Department of Energy research facility in Golden, CO.
NRZ: Non-Return to Zero. A family of PCM waveform sets for digital channel signaling. They use one voltage level to represent binary 1 and another for binary 0. In contrast to RZ signaling, voltage remains at one level for the duration of each bit period. Unipolar or non-polar NRZ signals are those that transition between 0V and a positive voltage, while bipolar or simply polar NRZ signals transition between a positive and a negative voltage, which has the advantage of reducing the signal’s power spectral density. Each approach has benefits for certain types of circuits or transmission lines. Sub-types of NRZ:; NRZ-L or NRZ(L) – L for Level. The higher voltage represents binary 1, and the lower voltage represents 0. Unipolar NRZ-L is the most widely familiar case because it’s used by the CMOS logic family.; NRZ-M or NRZ(M) – M for Mark. A change in level indicates a 1 (mark); no change indicates a 0 (space). Used mainly for digital magnetic tapes, NRZ-M and its complement, NRZ-S, are types of differential encoding.; NRZ-S or NRZ(S) – S for Space. The reverse of NRZ-M.; NRZ-I or NRZ(I) – I = Inverted. This term is used variously to mean NRZ-M, or NRZ-S, or NRZ-L with the voltages reversed, i.e., high voltage is binary 0 and low voltage is binary 1, an approach that’s simpler for certain electronic circuits to handle.; Compare Manchester coding.
NSF: National Science Foundation. See Internet.
NSFW: Not Safe For Work. A warning that an Internet link leads to images or audio that might do you no credit with your co-workers.
NSI: Network Solutions, Inc. A Herndon, VA firm that was responsible for creating new Internet domain names until about 1998. ICANN now performs this function. Now part of VeriSign, NSI still maintains the A root name server. See DNS.
NT: New Technology. Refers to Microsoft’s Windows NT operating system, and also to several associated technologies.
NTC: Negative Temperature Coefficient. A thermistor with resistance that decreases as temperature increases. The opposite type is PTC.
NTFS: New Technology File System. The file system that Microsoft introduced with Windows NT, replacing FAT and FAT32. It’s also the standard file system for Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8, and Windows 10. (High-end server versions of Windows 8 and 10 use ReFS for certain things.); NTFS cluster sizes range from 512 bytes to 64 kB. As with FAT/FAT32, only one file can use a given cluster. The Master File Table (MFT) maintains records about each file on the system, including cluster use. The Access Control List (ACL) lets the server administrator control who can access which files.; An NTFS file consists of at least two data streams. One holds the security information (access rights, etc.), and another holds the actual file data. If the “file” is actually a link, there will be another stream with link information. File information can also be placed in alternate data streams, which, incidentally, are hidden from the OS.
NTLM: NT (New Technology) LAN Manager. A set of network authentication protocols introduced with Windows NT, replacing the older LM (LAN Manager). Both LM and NTLM are now considered insecure.
NTP: Network Time Protocol. Developed to synchronize UTC clocks over packet-switched networks. It uses a 64-bit time value: 32 bits for seconds since 00:00:00 on 1 January 1900, and 32 bits for fraction of a second. The seconds count will roll over to zero in the year 2036. NTP servers are sometimes used for DRDoS attacks, because they respond to a NTP request by sending a much larger packet to the address contained in the request – which can be spoofed.
NTSC: National Television Standards Committee. A sub-group of the EIA. Also, the standard analog TV signal format they created in 1941 (black & white only, at first) and used in the US (until 2009) and Japan. The VSB video signal displays 525 raster-scan lines refreshed at 60 Hz, with a 4:3 horizontal-vertical aspect ratio. Compare PAL, SECAM.; Each 6 MHz wide NTSC channel contains the video carrier centered at 1.25 MHz, and the FM audio carrier at 5.75 MHz. North American broadcasters used 12 VHF channels numbered 2 to 13, occupying the 54-72 MHz, 76-88 MHz, and 174-216 MHz ranges; and 70 UHF channels numbered 14 to 83, occupying the 470-890 MHz range. Stations sharing a broadcast area had to use non-adjacent channels, although the presence of gaps between channels 4 & 5 and between channels 6 & 7 meant they could be used in the same area.; All high-power US TV stations stopped broadcasting analog NTSC signals in 2009, as required by the FCC, and changed over to ATSC signals.
NTT: Nippon Telephone & Telegraph, originally. A very big Japanese communications company.
NUC: Next Unit of Computing. A line of very small thin client PC that Intel launched in 2012, based on low-TDP versions of its desktop processors. Users have to add memory, internal SSD storage, and sometimes other hardware, or pay to have them pre-installed.
null-modem cable: An older term for some types of crossover cable.
null reference: In programming, a source-code object pointing to a memory location that hasn’t been written, meaning its contents are invalid. This is bad.
NVD: National Vulnerability Database. See CVE.
NVDIMM: Non-Volatile Dual In-line Memory Module. A hybrid memory type that fits into a DIMM socket and functions as main memory (DRAM), but retains state through power loss in a way transparent to the processor. It’s used in servers and high-end applications that need to recover quickly from power faults.
NVG: Night Vision Goggles.
NVM: Non-Volatile Memory. Same thing as NVRAM.
NVMe: Non-Volatile Memory Express. An industry standard protocol and interface for data storage, to support the higher speeds that SSDs can provide by using PCIe. M.2 NVMe devices can use up to 4 PCIe lanes. Manufacturers call out this feature as PCIe x2 or PCIe x4, just as they would with an expansion card that plugs into a PCIe slot of that size.
NVRAM: Non-Volatile Random Access Memory. Sometimes abbreviated as NVM or NOVRAM. A type of RAM that maintains state even when it loses main power, so it can store data that will be needed when the system is turned back on. The fastest types still need to draw small amounts of power from a dedicated battery or ultracap, while others, notably flash memory and FRAM, are genuinely unpowered.
NX: No-Execute. See DEP.
Nx586: A NexGen 80x86 CPU chip.
Nx686: A NexGen 80x86 CPU chip.
NXG: Next-Generation. LabVIEW NXG is a newer version of LabVIEW.
NXT-G: The LEGO Group graphical interface for programming LEGO robotics modules, based on NI’s popular LabVIEW GUI. Users can develop simple programs on NXT hardware, or develop more complex programs on a standard platform and upload them through NXT.
Nyquist rate: Named for American physicist Harry Nyquist (1889-1976), this is the maximum theoretical signaling rate of a given channel: twice the available bandwidth. Symbol rates that approach the Nyquist rate exhibit ISI and corresponding signal degradation due to the spreading of the pulses in time. The point at which this begins depends on the rolloff of the channel or filter. A channel with a rectangular response could achieve the full Nyquist rate without ISI, but this ideal channel is not physically realizable. On the receiving end, a digital signal must be sampled at a frequency at least twice its bandwidth (NOT its highest frequency) to be completely reconstructed. See also Shannon limit.
NZ-DSF: Non-Zero Dispersion Shifted Fiber. Single-mode optical fiber designed to reduce (but not eliminate) dispersion in the wavelength window around 1.55 µm, while reducing non-linearities. This compromise is struck because reducing chromatic dispersion actually worsens the effects of non-linearities.

Name	Meaning	Description
MCKI	message clock in	Timer signal for MSEI and MDI
MSEI[2]	message start/end in	Indicates start & end of MDI data; a design can have one MSEI, or two for more efficient message control
EVTI	event in	Control of processor breakpoints
MDI[m]	message data in	Data to processor, e.g., configuration and writes to on-chip memory & registers; number of lines m is scalable to customize data rate
MCKO	message clock out	Timer signal for MSEO and MDO
MSEO[2]	message start/end out	Indicates start & end of MDO data; a design can have one MSEI, or two for more efficient message control
MDO[n]	message data out	Data from processor, e.g., trace and read info; number of lines n is scalable to customize data rate
EVTO	event out	Optional; used for breakpoint status timing
RSTI	reset in	Resets the processor’s Nexus interface

Config.	Volts	Phases	Poles	Wires
1	125	single	2	2
2	250	single	2	2
5	125	single	2	3	grounding
6	250	single	2	3	grounding
7	277	single	2	3	grounding
8	480	single	2	3	grounding
9	600	single	2	3	grounding
10	125/250	single	3	3
11	250	three	3	3
12	480	three	3	3
13	600	three	3	3
14	125/250	single	3	4	grounding
15	250	three	3	4	grounding
16	480	three	3	4	grounding
17	600	three	3	4	grounding
18	120/208	three	4	4
19	277/480	three	4	4
20	347/600	three	4	4
21	120/208	three	4	5	grounding
22	277/480	three	4	5	grounding
23	347/600	three	4	5	grounding
24	347	single	2	3	grounding