Technical Glossary

Assembly Line Diagnostic Link, an OBD-I diagnostic connector used by General Motors vehicles for onboard diagnostics.

Amplitude Modulation, a technique where the amplitude of a carrier wave is varied in proportion to the information signal. Used in broadcasting since the early 1900s.

Authentication and Key Agreement, the 3GPP algorithm suite for mutual authentication in GSM (COMP128), UMTS (Milenage), and LTE/5G networks. 5G AKA (RFC 9441) provides enhanced security over 4G.

Absolute Radio Frequency Channel Number, a number that uniquely identifies a carrier frequency in GSM networks. Calculated from the center frequency using band-specific formulas.

A network addressing method where the same IP address is advertised from multiple locations. CDNs use Anycast routing to direct user traffic to the geographically nearest PoP.

Advanced Network and Services, a not-for-profit organization (1990-1995) created by IBM, MCI, and Merit to operate the ANSNET backbone at 45 Mbps, the first commercial-grade internet backbone.

Relating to sound or the science of sound waves. In transmission contexts, acoustic frequencies range from 20 Hz to 20 kHz, covering the range of human hearing.

Brain-Computer Interface, a direct communication pathway between the brain and an external device. EEG-based BCIs achieve 5-20 bits/min; invasive intracortical systems (Utah Array) achieve 40-90 chars/min via handwriting decoding.

A short-range wireless technology standard for exchanging data over short distances using UHF radio waves in the 2.4 GHz band.

Block Upconverter, an outdoor unit in VSAT satellite terminals that converts the intermediate frequency (70/140 MHz) from the IDU to the higher Ku/Ka-band transmit frequency.

Citizens Band Radio, a two-way radio service operating on 40 channels in the 27 MHz band. Popular for personal and trucking communications.

Content Delivery Network, a geographically distributed network of proxy servers that cache content closer to end users. Major CDNs operate 300-600+ PoPs with 200+ Tbps capacity.

Certified Ethical Hacker, an EC-Council certification validating penetration testing skills including footprinting, scanning, enumeration, system hacking, malware, and web application security.

Classless Inter-Domain Routing, an IP address allocation and routing aggregation method (RFC 1519) that replaced classful addressing and reduced routing table growth.

Continuous 4-Level Frequency Modulation, a 4FSK modulation format used in APCO P25 Phase 1 digital radio, transmitting 4,800 bits per second.

Controller Area Network 2.0, the second version of the CAN bus standard (ISO 11898) with 11-bit standard and 29-bit extended arbitration fields, up to 1 Mbps.

Cell Broadcast Channel, a GSM downlink channel used to broadcast SMS messages to all mobiles in a cell area, operating on SDCCH/4 combined channel configuration.

A mobile communication network divided into geographic cells, each served by a base station. Enables nationwide mobile voice and data coverage through handover between cells.

Cyclic Redundancy Check, an error-detection code used in CAN bus (15-bit CRC) and many other digital communication protocols to detect transmission errors.

Color Shift Keying, a modulation scheme in IEEE 802.15.7 VLC using three LED colors to encode 2 bits per symbol at 6 Mbps. Used in visible light communication systems.

Common Industrial Protocol synchronization, an IEEE 1588 PTP-based time synchronization profile for EtherNet/IP enabling nanosecond-level precision for coordinated motion control across distributed nodes.

A rule of thumb for FM bandwidth: BW = 2(Δf + fm) where Δf is peak frequency deviation and fm is the modulating frequency. Contains 98% of signal power.

COastal Battlefield Radar, a US Army/Raytheon OTH-B radar program for over-the-horizon target detection. Uses skywave propagation for long-range surveillance beyond the radar horizon.

Dynamic Adaptive Streaming over HTTP, an international standard (ISO/IEC 23009-1) for adaptive bitrate video streaming using MP4 fragments. Supported by YouTube, Netflix, and most CDNs.

Digital Video Broadcasting Terrestrial Second Generation, the European digital TV standard offering 30-50% more capacity than DVB-T through LDPC+BCH coding and larger FFT sizes.

An authentication, authorization, and accounting protocol (RFC 6733) used in LTE/5G networks. Applications include Gx (policy), Rx (IMS), and Sy (charging).

Diagnostic Trouble Code, a code stored by a vehicle's ECU when a fault is detected. OBD-II DTCs follow format P0301 (powertrain) or C0234 (chassis).

Digital Enhanced Cordless Telecommunications, a digital cordless phone standard operating at 1.88-1.90 GHz (Europe) or 1.92-1.93 GHz (US) with 120-channel TDMA and 32 kbps ADPCM voice.

The complementary filtering at the FM receiver that attenuates the high frequencies boosted by pre-emphasis, restoring the original frequency response and reducing hiss.

Domain Name System, the hierarchical naming system (RFC 1034/1035) translating domain names to IP addresses. Paul Mockapetris created DNS in 1984, replacing the earlier HOSTS.TXT file.

E-UTRA Absolute Radio Frequency Channel Number, the channel number used in LTE to identify uplink and downlink carrier frequencies, derived from band-specific formulas.

Enhanced GPRS, the EDGE mobile data technology in GSM networks offering up to 384 kbps using 8-PSK modulation and MCS-1 through MCS-9 coding schemes.

A family of computer networking technologies commonly used in local area networks, metropolitan area networks, and wide area networks.

Ethernet for Control Automation Technology, an industrial Ethernet protocol (IEC 61158) achieving 100 Mbps with sub-microsecond latency using 'processing on the fly' where frames are read and written as they pass through each node.

Enhanced Long Range Navigation, a ground-based positioning system operating at 90-110 kHz that serves as a backup to GPS. Provides accuracy of 10-20 meters, being revived for GPS backup by US/UK/South Korea.

Energy Sciences Network, a DOE-funded high-speed network connecting national laboratories at 100+ Gbps. Provides the science DMZ architecture pattern for high-performance research data transfers.

Fail Safe over EtherCAT, a safety protocol (IEC 61784-3) running over standard EtherCAT frames achieving SIL 3 safety performance. TwinSAFE uses FSoE for safety I/O and drives.

Frequency Modulation, a modulation technique where the frequency of the carrier wave is varied in proportion to the information signal.

January 1, 1983, when ARPANET officially switched from NCP to TCP/IP, marking the birth of the modern internet. All hosts had to adopt TCP/IP simultaneously (RFC 801).

Global Server Load Balancing, a technique for distributing traffic across multiple data centers using DNS or anycast. CDNs use GSLB to route users to the nearest healthy edge server.

Gaussian Minimum Shift Keying, the modulation format used in GSM with BT=0.3 and 1 bit per symbol. Provides a compact RF spectrum suitable for cellular networks.

Global Navigation Satellite System, an umbrella term for GPS (US), Galileo (EU), GLONASS (Russia), BeiDou (China), QZSS (Japan), and NavIC (India) satellite positioning systems.

GPRS Tunneling Protocol-Control, the control plane protocol (Gn/Gp/S5/S8 interfaces) managing tunnel creation, modification, and deletion in 4G/5G networks between SGW/PGW/MME nodes.

GPRS Tunneling Protocol-User Data, the user plane protocol (Gn/Gp/S1-U/S5/S8 interfaces) carrying actual subscriber data packets through GTP tunnels in 4G/5G networks.

GIAC Penetration Tester, a GIAC/SANS certification validating hands-on penetration testing skills including reconnaissance, exploitation, post-exploitation pivoting, and Azure security.

A free software development toolkit providing signal processing blocks for implementing SDR. Used for protocol analysis, fuzzing, and building custom RF systems. Pairs with RTL-SDR, HackRF, and USRP hardware.

HTTP Live Streaming, an adaptive bitrate streaming protocol developed by Apple using short 2-10 second segments of MPEG-TS video. Supports multiple quality levels for adaptive bitrate switching.

Home Subscriber Server, the master database in IMS/LTE that stores subscriber data including IMSI, authentication keys, subscription profiles, and location information.

A half-duplex SDR operating from 1 MHz to 6 GHz with 20 MHz bandwidth, created by Great Scott Gadgets. Supports transmission and reception of arbitrary signals for RF security research.

Infrared Data Association, a serial infrared data communication protocol standard (115 kbps to 1 Gbps) used in laptops and PDAs before Bluetooth made it obsolete.

Infrared Link Access Protocol, the data link layer of the IrDA stack, derived from HDLC, handling device discovery, framing, and error recovery.

A global network of interconnected computer networks using TCP/IP protocols to link billions of devices worldwide. The foundation of modern digital communication.

A consortium of 500+ US universities and research institutions operating advanced networking for research, including the 100 Gbps AL2S backbone and Science DMZ architectures.

IP Multimedia Subsystem, the 3GPP architecture enabling all-IP voice, video, and data services on LTE and 5G networks. Core components include P-CSCF, S-CSCF, and HSS.

Integrated Services Digital Network, a digital telephone network standard providing simultaneous voice and data over circuit-switched networks. BRI (2B+D) or PRI (23B+D US / 30B+D Europe).

ISDN User Part, an SS7 protocol (Q.761-Q.764) for call setup and teardown messages including IAM (Initial Address), ACM (Address Complete), ANM (Answer), REL (Release), and RLC (Release Complete).

Jindalee Operational Radar Network, Australia's over-the-horizon radar system providing 1000-3000 km coverage of northern maritime approaches. Operates at HF 5-30 MHz with multiple megawatts peak power.

A covert BLE-based device by Samy Kamkar that secretly logs keystrokes from Microsoft wireless keyboards. Uses a Nordic nRF24LU1+ chip to sniff 2.4 GHz keystroke packets at up to 80 meters.

Low-Noise Block downconverter, the outdoor unit in a satellite dish that receives the Ku/Ka-band signal, amplifies it, and converts it to a lower IF frequency for the indoor unit.

Low-Density Parity-Check, an error-correcting code used in 5G NR and DVB-T2 that approaches the Shannon limit. 3GPP selected LDPC for 5G data channels.

Long Range, a spread spectrum modulation technique for low-power wide-area networks. Enables long-range communication with low power consumption.

Radio frequencies below 300 kHz, used for long-distance navigation and communication due to excellent groundwave propagation.

Light Fidelity, a VLC technology by pureLiFi using IEEE 802.11bb (2023 Light Communications standard) with 10 Mbps minimum guaranteed data rate. Light Antenna ONE is the first commercial Li-Fi device.

Multiplex, the composite baseband signal in FM stereo broadcasting containing L+R (50 Hz-15 kHz), 19 kHz stereo pilot, and L-R DSB-SC subcarrier at 38 kHz modulated at 15 kHz.

A military GPS signal (L1/L2 1176.45 MHz) with higher power and improved anti-jam/antenna beamforming capabilities. Features the Coarse/Acquisition navigation message and encrypted P(Y)-code successor.

Michigan Educational Research Information Triad, a consortium founded at University of Michigan (1966) that evolved into a key internet backbone operator and managed NSFNET before the commercial transition.

The first widely-used web browser (1993) by NCSA at University of Illinois. Added inline images to web pages and ran on Unix/Windows/Mac. Created by Marc Andreessen; spawned Netscape Navigator.

Modulation and Coding Scheme, the combination of modulation order and code rate determining throughput in EGPRS (MCS-1 through MCS-9) and LTE/5G.

A family of NFC-compatible RFID chips by NXP including Classic (Crypto-1, broken), Ultralight, DESFire (AES-128), and SAM products for secure access applications.

Electromagnetic waves with frequencies from 300 MHz to 300 GHz, used for radar, satellite communications, and wireless networking.

A brain-computer interface company founded by Elon Musk. The N1 implant contains 1024 electrodes across 64 threads, surgically implanted by a robot. FDA-approved human trials began 2024 for tetraplegia.

National Science Foundation Network, a research network (1986-1995) that connected supercomputer centers at 45 Mbps and served as the internet backbone before commercialization. Replaced by commercial ISPs in 1995.

The dominant browser of the 1990s (1994-2007) created by Marc Andreessen and Jim Clark. Invented SSL (Netscape Navigator 2.0), cookies, and JavaScript. Market share peaked at 80%+ before IE surpassed it.

NOmbred STAtistique RADAR MONderne US, a French Thales OTH-B skywave radar operating 3-30 MHz with 32 antenna columns in an M-curve shape. Detects ships and aircraft at 1000-3500 km.

Neural Engineering System Design, a DARPA program targeting high-resolution neural interfaces: read 10^6 neurons, write to 10^5 neurons, interact with 10^3 neurons full-duplex.

Near Field Communication, a set of communication protocols enabling two electronic devices to establish communication within 4 cm of each other.

5G NR Absolute Radio Frequency Channel Number, calculated as FREF = FREF-Offs + ΔF × NREF where ΔF is 5 kHz for FR1 and 15 kHz for FR2.

Interconnected systems of computers, devices, and infrastructure that exchange data using wired or wireless links. The internet is the largest network of networks.

On-Board Diagnostics, a vehicle's self-diagnostic and reporting system that provides access to various vehicle subsystems.

Offensive Security Certified Professional, a 24-hour hands-on penetration testing certification requiring compromise of live machines. One of the most respected practical security certifications.

Over-the-Horizon Radar, exploits ionospheric reflection to detect targets 1000-3500+ km beyond the visual horizon. Major systems include JORN (Australia), NOSTRADAMUS (France), COBRA (US).

Communication technology using visible light or infrared to transmit information. Includes fiber optics, free-space optics, and visible light communication (VLC).

Process Field Net, a Siemens industrial Ethernet protocol (IEC 61158) with PROFINET IRT (isochronous real-time, 31.25 μs cycle, IEEE 1588 DC sync) for motion control and RT for general automation.

A safety protocol (IEC 61784-3) for PROFINET enabling SIL 3 safety communications between safety PLCs and safety I/O. Uses telegram redundancy and watchdog timers.

An audio processing technique that boosts high frequencies before transmission in FM broadcasting (75 μs in the Americas, 50 μs in Europe/Japan) to improve signal-to-noise ratio.

Point of Presence, a geographically distributed network location where CDN edge servers cache content. CDNs operate hundreds to thousands of PoPs globally.

Project 25, the digital radio standard for public safety in North America. Phase 1 uses FDMA with C4FM; Phase 2 adds 2-slot TDMA for doubled capacity.

Parameter ID in OBD-II, a hex code identifying a specific engine parameter (e.g., 0x0C = RPM, 0x0D = vehicle speed, 0x05 = coolant temperature).

Pulse Position Modulation, used in IrDA FIR (4PPM) and VLC to encode data by varying the position of an optical pulse within a time slot.

Radio Detection and Ranging, a system that uses radio waves to detect the position, speed, and range of objects. Transmits pulses and measures reflections to determine distance.

Philips RC-5 infrared remote protocol using 36 kHz carrier, 14-bit Manchester-encoded frames with start bit, toggle bit, system address, and command.

A Software-Defined Radio based on the Realtek RTL2832U chip, originally a DVB-T USB dongle repurposed for SDR. Covers 500 kHz to 1.7 GHz and is the most affordable entry into SDR ($20-30).

The technology of using electromagnetic waves in the radio frequency spectrum to transmit and receive information wirelessly. Encompasses broadcasting, two-way communication, and data transmission.

Radio Frequency Identification, a technology using electromagnetic fields to automatically identify and track tags attached to objects. Operates at LF (125 kHz), HF (13.56 MHz), and UHF (860-960 MHz).

Radio Data System, a communications protocol (EN 50067) embedding digital information in FM broadcasts at 57 kHz subcarrier. Transmits station ID, traffic alerts, and song info at 1187.5 bps using Reed-Solomon encoding.

A rolling code attack demonstrated by Samy Kamkar using a $30 radio device to capture and replay key fob signals. Jams the real signal while transmitting a previously intercepted code to unlock vehicles.

An endovascular BCI by Synchron that is implanted via the jugular vein into the motor cortex's superior sagittal sinus. No open-skull surgery required; uses a 10 MHz stent with 16 electrodes.

An object placed in orbit around a planet to relay communications, broadcast signals, or observe Earth and space. Communication satellites enable global telephone, internet, and broadcast services.

Security Edge Protection Proxy, a component in 5G networks that protects inter-carrier signaling by authenticating and encrypting messages between operators.

Session Initiation Protocol, an IETF text-based signaling protocol (RFC 3261) for VoIP and real-time communications. Uses ports 5060/5061 and SDP for media negotiation.

Signaling System #7, an ITU-T Q.700 series protocol for telephone call setup and management. Uses MTP, SCCP, TCAP, and ISUP layers. Has known security vulnerabilities.

Signaling Connection Control Part, an SS7 network layer protocol providing connectionless and connection-oriented services above MTP Level 3, used to address individual mobile subscribers.

Subscription Concealed Identity, a privacy mechanism in 5G that encrypts the subscriber's SUPI using ECIES scheme A with the operator's public key, preventing IMSI catchers.

Subscription Permanent Identifier, the 5G equivalent of the IMSI - a unique 15-digit globally unique identifier assigned to each mobile subscription.

Radio frequencies in the 3 to 30 MHz range used for long-distance international broadcasting and amateur radio.

Global electromagnetic resonance of the Earth-ionosphere cavity at 7.83 Hz (fundamental) and harmonics at 14.3, 20.8, 27.3, 33.8 Hz, excited by worldwide lightning.

An undersea fiber optic cable laid on the ocean floor to carry international internet and telephone traffic. Over 99% of transcontinental data travels through submarine cables.

Transaction Capabilities Application Part, an SS7 application layer protocol (ANSI/ITU-T) supporting operations like MAP queries between HLR and VLR for mobile subscriber lookups.

Transmission Control Protocol over Internet Protocol, the foundational protocol suite of the internet. TCP handles reliable data delivery; IP handles addressing and routing.

Temporary Mobile Subscriber Identity, a temporary identifier assigned by the network to protect the subscriber's IMSI from interception during mobile communications.

A telecommunications device that transmits voice and data over distances using electrical signals through wires or radio waves. The modern system connects to the PSTN.

The transmission of moving images and sound over distances, first via analog signals and now via digital encoding. Transforms visual content into electromagnetic signals for broadcast or cable delivery.

Terrestrial Trunked Radio, a digital mobile radio standard designed for professional users such as emergency services and military.

A silicon-based intracortical BCI electrode array with 96 needle-like shanks, each 1-10 mm long with 10-12 electrodes at the tip. Manufactured by Blackrock Neurotech; used in BrainGate trials achieving 90 chars/min.

Universal Software Radio Peripheral, a modular SDR platform by Ettus Research/National Instruments covering DC to 6 GHz with up to 160 MHz bandwidth. Used for 4G/5G research, spectrum analysis, and protocol development.

Unlicensed National Information Infrastructure, the 5 GHz WiFi spectrum bands: UNII-1 (5150-5250 MHz), UNII-2 (5250-5350 MHz), UNII-2e (5470-5725 MHz), UNII-3 (5725-5850 MHz).

Vulnerability Disclosure Program, a formal process allowing security researchers to report vulnerabilities. Government VDPs include DoD VDP and CISA VDP.

Visible Light Communication, data transmission using visible light from LEDs at 380-780 nm, defined by IEEE 802.15.7, supporting data rates from 11.67 kbps to 96 Mbps.

Visible Light Positioning, a localization technique using LED transmitters and photodiode receivers to achieve centimeter-level positioning accuracy based on TDOA/RSS/TOA algorithms.

Very Small Aperture Terminal, a two-way satellite ground station with a small dish (0.75-2.4 m) used for broadband internet, data, and voice services. Consists of outdoor unit (BUC/LNB) and indoor unit (IDU).

The first web browser and editor by Tim Berners-Lee at CERN (1990), running on NeXT computers. The foundational software that introduced HTTP, HTML, and URLs as we know them.

World Wide Web Consortium, the main standards organization for the web founded by Tim Berners-Lee in 1994. Publishes recommendations for HTML, CSS, XML, and web architecture.

Web Hypertext Application Technology Working Group, a living standard community that maintains HTML and DOM standards. Founded in 2004 by Apple, Mozilla, and Opera in opposition to W3C's XHTML direction.

Wired Equivalent Privacy, an early WiFi security protocol using RC4 encryption. Now considered insecure and replaced by WPA.

WiFi Protected Access, a security protocol replacing WEP with stronger TKIP encryption. Later superseded by WPA2 and WPA3.

A family of wireless networking protocols based on the IEEE 802.11 standards, commonly used for local area networking and internet access.

A low-power, low-data-rate wireless networking technology based on the IEEE 802.15.4 standard, used for home automation and IoT.