Telecom, Networking & IT

The terminology of traditional phone networks, voice over IP, and switching systems.

• 411also directory assistance
  A telephone number dialed to access local directory assistance.
• ACDalso automatic call distributor
  A telephony system that answers incoming calls and routes them to a specific agent or department based on predefined rules.
• Address messagealso Initial Address Message, IAM
  A signaling packet that carries the routing information and caller details required to set up a telephone call.
• Ader receiver
  An early design of telephone receiver utilizing a magnetized metal ring to improve sound transmission.
• All-figure number
  A telephone dialing format consisting entirely of digits rather than alphanumeric exchange codes.
• ANIalso Automatic Number Identification
  Automatic Number Identification is a system that determines the billing telephone number of a calling party.
• Answering machine
  A customer-premises device that automatically answers calls and records audio messages.
• Baby Bellalso RBOC, Regional Bell Operating Company
  One of the regional telephone companies created by the historic breakup of the original AT&T monopoly. Shop talk
• Base communicationsalso base comms
  The localized telecommunications infrastructure and services supporting a military installation.
• BHCAalso Busy-Hour Call Attempts
  Busy-Hour Call Attempts, a metric used to evaluate the peak processing capacity of a telephone exchange.
• Blocked
  A state where a call or connection attempt is rejected by the network switch or firewall.
• BORSCHT
  The essential functions provided by a subscriber line interface circuit in a telephone exchange.
• Busy signalalso engaged tone
  A repeating audio tone that informs a caller the dialed line or network path is in use.
• Call centeralso contact center
  A centralized facility equipped to handle large volumes of inbound or outbound telephone requests.
• Call delay
  The time a telephone connection waits in a queue at an automatic switch because no outgoing circuits are free.
• Call forwardingalso call diversion
  A telephony feature that automatically redirects incoming calls to a different designated number.
• Call historyalso call log
  A logged record of incoming, outgoing, and missed telephone calls for a specific line or device.
• Call treealso phone tree
  A hierarchical notification plan where each person contacted must then telephone a specific list of subsequent people.
• Callback
  A return telephone call or automated connection made to verify a user's identity.
• Calleealso called party, B-party
  The receiving party in a telephone call or communications session.
• Calleralso calling party, A-party
  The person or device that initiates a telephone call or connection.
• CASalso channel-associated signaling
  Channel-associated signaling, a method where call control information shares the same circuit as the voice path.
• CDRalso SMDR
  A data record produced by a telephone exchange containing the details of a specific call.
• Clearingalso call clearing, teardown
  The process of tearing down a telephone connection and releasing the network resources.
• CLEC
  A competitive local exchange carrier is a telecom provider competing with the established regional telephone company.
• CMS
  A call management system is a software platform used to monitor, route, and report on telephone traffic in a call center.
• COCOT
  A customer-owned coin-operated telephone is a privately purchased payphone connected to the public network.
• Common carrier
  A telecommunications company that provides public network services without discriminating against specific users or content.
• Connect time
  The total duration that a circuit-switched communications link remains active.
• CPCalso Calling Party Control, open loop disconnect
  A momentary drop in line voltage used to signal that the calling party has hung up.
• CPEalso customer-premises equipment, customer-provided equipment
  Telecommunications hardware located at the subscriber's physical location rather than the provider's facility.
• Crossbar switchalso crossbar, X-bar
  An electromechanical switching system that routes calls by closing contacts at the intersections of a grid.
• Crossed linealso crosstalk
  A fault in a telephone network that causes voices from another active call to bleed into a connection.
• CSalso circuit-switched, circuit switching
  A network design where a dedicated physical or logical path is established for the duration of a session.
• CSPalso communications service provider, telco
  An umbrella term for companies that offer telecommunications, internet, or media transmission services.
• CTIalso Computer Telephony Integration
  Computer telephony integration links phone systems with software applications.
• Cutover
  The rapid transition from an old system to a new one with minimal downtime.
• Data set
  A historic term for an early modem used to connect digital terminals to analog telephone lines.
• Day letter
  A historic deferred telegraph service delivered during business hours.
• DDDalso direct distance dialing
  Direct distance dialing allows callers to route long-distance calls without an operator.
• DDIalso direct dial-in, direct inward dialing
  Direct dial-in routes incoming calls directly to a specific extension.
• Debug
  The process of sweeping a room, telephone line, or network facility to detect and remove hidden surveillance devices.
• DECT
  A digital wireless standard used primarily for cordless telephones and enterprise voice systems.
• Dial-aroundalso casual calling, 10-10 dialing
  A telecom service accessed by dialing a specific prefix to bypass the default long-distance carrier.
• Diverteralso call diverter
  A device or circuit that forwards incoming telephone calls to another destination.
• Double talk
  A condition in a voice circuit where both parties speak simultaneously, often confusing echo cancellers.
• Engaged tonealso busy signal, busy tone
  An audible network signal indicating that the dialed number or circuit is in use.
• ERC
  An easily-recognizable code is a telephone area code with a specific repeating digit pattern.
• ESS
  A telephone exchange that uses solid-state electronics and computerized switching.
• Exchangealso central office, wire center
  A physical building or the specific set of telephone numbers routed through it.
• Exit codealso international access code, IDD prefix
  A prefix dialed to route a telephone call outside the caller's national network.
• Extensionalso ext
  A short internal telephone number assigned to a specific endpoint within a private branch exchange.
• Fast busy signalalso reorder tone, congestion tone
  A rapid pulsing tone indicating that the telephone network cannot route the call.
• Fast telegramalso full-rate telegram
  A historic telegraph service tier guaranteeing immediate transmission and delivery.
• Flash cutalso flash cutover
  An immediate, instantaneous transition from an old system to a new one without a phase-in period. Shop talk
• Ghost callalso phantom call
  A telephone call that rings with no one on the other end, often caused by automated dialers or network routing errors. Shop talk
• Glarealso call collision
  A call collision that happens when an incoming and outgoing call seize the same trunk circuit simultaneously.
• Hardlinealso landline
  A physical, wired communications connection rather than a wireless one. Shop talk
• Helpline
  A dedicated telephone routing service designed to connect callers with specialized support or emergency assistance.
• Hold timealso queue time
  The duration a caller remains in an active queue before an agent answers or the call drops.
• Hook flashalso flash, switchhook flash
  A brief interruption of the line current used to signal the telephone exchange.
• Huntingalso line hunting
  The automated process of routing an incoming call through a group of lines until an idle one is found.
• ILEC
  The established regional telephone company that owned the original copper wire monopoly before market deregulation.
• In-band signaling
  The transmission of network control signals over the same channel used for the actual voice or data payload.
• IPBXalso IP-PBX
  An Internet Protocol private branch exchange handles internal business telephone switching over a local data network.
• ISDNalso Integrated Services Digital Network
  Integrated Services Digital Network is an older standard for transmitting digital voice and data over standard telephone lines.
• Keysetalso key telephone, multiline phone
  A multi-button telephone instrument used in business environments to access multiple lines and switching features.
• LAPD
  A Layer 2 data link protocol used in ISDN networks to ensure error-free communication on the D channel.
• LEC
  A regulatory term for a local telephone company that provides service within a specific geographic area.
• LIR
  A defined geographic area where telecommunications carriers exchange local traffic without incurring long-distance toll charges.
• Local loopalso last mile, subscriber loop
  The physical wiring connecting a customer premises to the nearest telephone exchange.
• LUDsalso local usage details
  Local usage details, the itemized billing records of local telephone calls made from a specific line. Shop talk
• Machinealso answering machine
  A shorthand term for an answering machine or a voicemail system. Shop talk
• MNPalso FMNP
  The abbreviation for mobile number portability, a system allowing users to keep their phone numbers when changing carriers.
• MTSOalso MSC
  The abbreviation for Mobile Telephone Switching Office, the central routing hub for a cellular network.
• Netcoalso network company
  The division or spinoff of a telecommunications company that owns and operates the physical network infrastructure. Shop talk
• Netphonealso IP phone, VoIP phone
  An early or informal term for a telephone that routes calls over the internet rather than the traditional public switched network. Shop talk
• Night letter
  A historic telegram service sent overnight at a discounted rate.
• Operating time
  The total duration a telecommunications circuit or facility is occupied by a user request.
• OSSalso operations support system
  The software systems used by telecommunications service providers to manage their networks.
• Out-of-band signalingalso common channel signaling
  A telecommunications method where control signals travel on a different channel than the voice or data traffic.
• Party line
  A local telephone loop shared by multiple subscriber households.
• Paster
  A wiring diagram glued to the inside of a telephone housing.
• PBX
  A private telephone network used within a company or organization.
• Person-to-person
  An operator-assisted telephone call where billing only begins if a specifically named individual answers.
• Phone treealso IVR menu, call tree
  An automated, multi-level voice menu that routes callers based on their keypad or spoken responses.
• POTSalso plain old telephone service
  Plain old telephone service is the traditional analog voice transmission network using copper wires.
• Prefix
  The initial digits of a telephone number that route the call to a specific geographic region or service type.
• PRI
  The primary rate interface is an enterprise telecommunications standard for carrying multiple voice and data channels.
• Primary rate interfacealso PRI
  An enterprise-grade ISDN connection that bundles multiple digital voice and data channels over a single physical line.
• Private branch exchangealso PBX
  A private telephone switching system installed on a customer premises.
• PSTN
  The global infrastructure of circuit-switched telephone networks operated by national and regional carriers.
• PTC
  An international non-profit organization that promotes the advancement of information and communication technologies.
• Pulse dialingalso rotary dialing, decadic dialing
  A legacy telephone signaling method that rapidly connects and disconnects the line to indicate digits.
• Relayalso telecommunications relay service, TRS
  A telecommunications service that facilitates calls between users with hearing or speech disabilities and users of standard telephones.
• Ring cadencealso ring pattern
  The specific timing pattern of ringing voltage applied to a telephone line.
• Ring offalso hang up, clear down
  The act of terminating a telephone connection and releasing the circuit.
• Ring out
  To place an outbound call from a private network to the public telephone network.
• Ring time
  The total duration a telephone rings before it is answered or goes to voicemail.
• Ringbackalso ringback tone, RBT
  The audible tone sent to a caller to indicate the destination phone is ringing.
• Ringdownalso automatic ringdown, ARD
  A dedicated telephone circuit that automatically signals the other end when the handset is lifted.
• Ringer equivalence numberalso REN
  A measurement of the electrical load a telephone device places on a landline circuit.
• Rubberalso rubberneck
  To eavesdrop on a telephone conversation without the participants knowing. Shop talk
• Saturation
  The state where a network or component has reached its maximum traffic-handling limit.
• SDP
  Service Data Point is a node in an intelligent network that holds subscriber databases and service scripts.
• Servco
  The customer service and retail division of a telecommunications company. Shop talk
• Simplex
  A communication channel that transmits data in only one direction.
• Slamalso slamming
  To switch a customer's telephone service provider without their authorization. Shop talk
• Speaking
  A standard verbal response indicating that the person who answered the call is the one being asked for.
• Station-to-station
  A traditional operator-assisted toll call billed to the calling party regardless of who answers.
• STDalso subscriber trunk dialling, subscriber toll dialing
  Subscriber trunk dialling, the historic system allowing callers to route long-distance calls without an operator.
• Straight
  A telegraphic message routed and delivered at full priority without delay.
• Subscriber trunk diallingalso STD, direct distance dialing
  The automated telephone exchange system that allows callers to dial long-distance numbers directly.
• Subswitch
  A subordinate switching unit that handles local routing before passing traffic to a primary switch.
• Supergroup
  A multiplexed bundle of 60 voice channels in traditional analog carrier systems.
• SVoSIP
  Secure Voice over Secure IP, a highly encrypted voice communication protocol.
• Switchboard
  A manual or electronic panel used by operators to route incoming telephone calls.
• Switchroom
  A secure, climate-controlled room housing telecom switching equipment.
• T-carrier
  A North American standard for digitally multiplexing voice and data signals.
• TCAP
  Transaction Capabilities Application Part is a protocol in the SS7 suite used for non-circuit-related data exchange.
• TDDalso TTY, text telephone
  A telecommunications device for the deaf is a terminal that allows text communication over a standard telephone line.
• Teleassistancealso remote support
  Remote technical or medical support provided over a telecommunications network.
• Teledensity ratealso teledensity, telephone penetration rate
  A metric representing the number of active telephone connections per one hundred inhabitants in a specific area.
• Telephone exchangealso central office, exchange
  A central system of switches that routes calls between subscribers.
• Time-assignment speech interpolationalso TASI
  An analog technique that increases channel capacity by allocating bandwidth only when a person is actively speaking.
• TMalso telephone manager
  A telephone manager is an older administrative role or software module responsible for handling phone system operations.
• Tone dialingalso DTMF
  A method of telephone signaling that uses specific audio frequencies to represent dialed digits.
• Touch-tone dialingalso Touch-Tone, DTMF
  The Bell System's trademarked implementation of dual-tone multi-frequency telephone signaling.
• Trombonealso hairpin, tromboning
  To route a signal back and forth over the same path or to a central switch before reaching its destination. Shop talk
• Trunk callalso toll call, long-distance call
  A historic long-distance telephone call routed through major intercity exchanges.
• Unhold
  To resume an active telephone connection that was previously paused.
• Vanity number
  A custom telephone number chosen because its digits map to a specific, memorable word on a dialpad.
• Voice over broadbandalso VoBB
  The delivery of residential or small business telephone service over a high-speed internet connection.
• Voice over IPalso IP telephony
  A technology that delivers voice communications and multimedia sessions over Internet Protocol networks.
• Voicebandalso voice frequency, VF
  The specific range of audio frequencies transmitted over a traditional analog telephone network.
• VoIPalso Voice over Internet Protocol
  Voice over Internet Protocol is the standard technology for transmitting telephone calls over data networks.
• Webphonealso softphone
  A software application or hardware device that makes telephone calls over the internet.
• WLNP
  Wireless local number portability allows a subscriber to keep their mobile phone number when changing service providers.
• WNP
  Wireless number portability is the system enabling cellular customers to retain their phone numbers across different carriers.
• Zero prefix
  A leading zero used in domestic telephone numbers to access the national trunk dialing network.

The vocabulary of cellular infrastructure, radio spectrum, and mobile data standards.

• 2G
  The second generation of cellular network technology that introduced digital voice encryption.
• 3G
  The third generation of mobile telecommunications technology, known for introducing mobile broadband to cellular networks.
• 3GPP
  A global consortium that develops protocols for mobile telecommunications.
• ACCH
  A signaling channel used in cellular networks to manage call parameters alongside user data.
• Acquisition time
  The duration required for a receiver to lock onto enough signals to calculate its initial position or synchronize.
• AMPSalso Advanced Mobile Phone System
  Advanced Mobile Phone System is an early analog cellular network standard used for voice.
• Android
  A mobile operating system developed by Google, or a device running that system.
• Appalso application
  A software application designed to run on a mobile device or specific operating system. Shop talk
• Base station subsystemalso BSS
  The section of a cellular network that manages radio links between mobile devices and the core network.
• Black spotalso dead zone, not-spot
  A localized geographic area where cellular or radio coverage drops out completely. Shop talk
• Break up
  The degradation of an audio or digital signal resulting in intermittent dropouts.
• CCIalso co-channel interference
  Co-channel interference, crosstalk caused by two transmitters using the exact same frequency.
• CDMA
  A channel access method where multiple transmitters send information simultaneously over a single communication channel.
• Cell
  The geographic area covered by a single base station in a mobile network.
• Cellular
  Relating to a network architecture that divides a geographic area into multiple radio coverage zones.
• Coveragealso footprint
  The geographic area where a wireless network provides a usable signal to client devices.
• CQIalso channel quality indicator
  A metric transmitted by a mobile device to the base station to report current radio channel conditions.
• CSDalso circuit switched data
  An older cellular data transmission method that ties up a dedicated voice channel for a data connection.
• D2M
  Direct-to-Mobile, a broadcasting technology that sends video or data straight to smartphones.
• Data
  Digital information transmitted over a cellular network rather than a local wireless connection. Shop talk
• DCHalso dedicated channel
  A dedicated channel carries user data and control information in UMTS networks.
• Dead zonealso not-spot
  A geographic area where a wireless network provides no coverage.
• Downlink
  The transmission path from a satellite, cell tower, or network core to the end-user device.
• DPCCH
  Dedicated Physical Control Channel carries signaling and control information between a mobile device and a UMTS base station.
• DPCH
  Dedicated Physical Channel is the combined radio link carrying both user data and control signaling for a specific mobile user.
• DPDCH
  Dedicated Physical Data Channel is a UMTS radio channel carrying user payload.
• EDGE
  Enhanced Data rates for GSM Evolution is a legacy mobile data standard that improved 2G speeds.
• EGPRS
  Enhanced General Packet Radio Service is the formal technical name for the EDGE mobile data standard.
• eSIM
  An embedded Subscriber Identity Module permanently soldered into a device.
• ETSI
  A European organization that creates standards for information and communications technologies.
• FCDalso floating cellular data, floating car data
  A method of collecting traffic and movement data by tracking active mobile devices in transit.
• FDDalso frequency-division duplex
  A transmission method that uses separate frequency bands for sending and receiving data.
• Femtocell
  A low-power, short-range cellular base station designed to provide indoor coverage.
• Forward linkalso downlink
  The communication path from a fixed base station to a mobile user.
• GIPalso GSM Interworking Profile
  GSM Interworking Profile, a standard allowing DECT cordless phones to interface with a GSM mobile network.
• GPRSalso General Packet Radio Service
  General Packet Radio Service, an early mobile data standard built on top of 2G GSM networks.
• GSM
  Global System for Mobile communications is a standard for digital cellular networks.
• HS-DSCH
  High Speed Downlink Shared Channel is a transport channel in UMTS networks used to deliver high-speed data to mobile devices.
• HS-PDSCH
  High Speed Physical Downlink Shared Channel carries the actual user data payload in HSDPA networks.
• HS-SCCH
  High Speed Shared Control Channel is a signaling channel that tells a mobile device how to decode incoming high-speed data.
• HSCSDalso High-Speed Circuit-Switched Data
  High-Speed Circuit-Switched Data is an early enhancement to GSM networks that combined multiple time slots to increase data rates.
• HSDPA
  A 3G mobile telephony protocol that provides enhanced download speeds.
• HSUPA
  A 3G mobile telephony protocol designed to increase upload data speeds.
• IMS
  The standardized architectural framework that delivers voice and multimedia services over packet-switched cellular networks.
• IMSI
  A unique 15-digit number embedded on a SIM card that identifies a specific cellular subscriber to the network.
• MMS
  The abbreviation for Multimedia Messaging Service, a standard for sending media over cellular networks.
• Mobile dataalso cellular data
  Internet traffic routed over a cellular radio network instead of a local Wi-Fi connection.
• Mobile stationalso MS
  The complete set of user equipment required to communicate with a cellular network.
• Mobile virtual network operatoralso MVNO
  A cellular service provider that leases radio network capacity from a physical network owner.
• Multipathalso multipath propagation, multipath interference
  The phenomenon where a transmitted radio signal reaches a receiver by two or more separate paths.
• Network subsystemalso NSS, core network
  The core switching network of a GSM mobile phone system.
• NSAalso Non-Standalone Architecture
  Non-Standalone Architecture, a 5G deployment method relying on a 4G core.
• On silent
  A device state where audible alerts for incoming calls and messages are suppressed. Shop talk
• Page
  To send a short numeric or text message to a dedicated wireless receiver.
• Pageralso beeper
  A small wireless receiver designed to display short numeric or text messages.
• PCSalso Personal Communications Service, Personal Communication System
  A set of wireless communication technologies operating in the 1900 MHz frequency band.
• PDCalso Personal Digital Cellular
  A historic 2G mobile telecommunications standard developed and used exclusively in Japan.
• Picocell
  A small cellular base station designed to provide localized coverage within a building or dense area.
• Push notificationalso push message
  An automated message sent from a server to a client application without a specific request from the user.
• Radio-frequency identificationalso RFID
  A wireless tracking technology that uses electromagnetic fields to automatically identify and read tags attached to objects.
• Refarmingalso spectrum refarming
  The process of repurposing existing radio spectrum bands for newer communication technologies.
• Reverse linkalso uplink
  The radio transmission path from a mobile device back to the base station.
• RFID
  Radio-frequency identification, a system that uses electromagnetic fields to track tags.
• Roamalso Roaming
  To connect a mobile device to a network other than its home network.
• SIMalso SIM card
  A Subscriber Identity Module card that authenticates a device on a cellular network.
• Smartphone
  A mobile phone equipped with an advanced operating system and computing capabilities.
• Spectrumalso radio spectrum
  The entire range of electromagnetic frequencies available for transmitting wireless communication signals.
• Spimalso IM spam, SMS spam
  Unsolicited junk messages sent to mobile phones or instant messaging platforms. Shop talk
• Spot beam
  A highly concentrated satellite signal directed at a specific, limited geographic area on the ground.
• SRESalso Signed Response
  The signed response generated by a SIM card to prove its identity to a cellular network.
• Standby time
  The estimated duration a battery-powered device can remain powered on and connected to a network without active use.
• Talk time
  The maximum continuous duration a mobile phone can be used for a call on a single battery charge.
• Telecommunications toweralso cell tower, mast
  A tall structure designed to elevate antennas and transmission equipment for wireless networking and broadcasting.
• Tethered
  Connected to another device to share a mobile internet connection.
• UEalso User Equipment
  The end-user device that connects to a cellular network base station.
• UMTS
  A third-generation cellular standard based on wideband code division multiple access.
• Unlockalso Unlocked, factory unlocked
  To remove software restrictions that tie a mobile device to a specific network carrier.
• Voice over NRalso VoNR, Voice over New Radio
  A standard for delivering voice calls over 5G New Radio standalone networks.
• WAEalso Wireless Application Environment
  The application layer framework within the Wireless Application Protocol suite.
• WAPalso Wireless Application Protocol
  An early technical standard for accessing information over a mobile wireless network.
• WiMAXalso 802.16
  A wireless broadband standard designed to deliver high-speed data over long distances.
• Wireless internet
  A broadband connection delivered over cellular radio networks rather than physical cables.
• WTAI
  Wireless Telephony Applications Interface is a protocol linking web content to cellular phone functions.

The language of routing protocols, packet switching, and internet service delivery.

• 802.11ialso WPA2
  An IEEE amendment that defines security mechanisms for wireless local area networks.
• AAL
  A protocol layer that formats higher-level data into standard cells for asynchronous transfer mode networks.
• AAL2
  An ATM adaptation layer designed for variable-bitrate, timing-dependent traffic like compressed voice.
• AAL5also SEAL
  An ATM adaptation layer optimized for transporting standard data traffic like IP packets.
• Acknowledgmentalso ACK
  A control message sent by a receiver to confirm that a data packet arrived intact.
• ADSLalso Asymmetric Digital Subscriber Line
  Asymmetric Digital Subscriber Line provides broadband internet access over traditional copper telephone lines.
• Asymmetric digital subscriber linealso ADSL
  A broadband technology that provides faster download speeds than upload speeds over traditional copper telephone lines.
• ATMalso Asynchronous Transfer Mode
  A telecommunications standard that switches traffic in fixed-size 53-byte cells.
• Away messagealso auto-reply, out of office
  An automated reply triggered by incoming messages or calls when a user is offline or unavailable.
• BBSalso bulletin board system, bulletin board service
  A bulletin board system hosted on a computer that users access over a dial-up connection.
• Beaconing
  The periodic transmission of small packets used to announce presence or signal network faults.
• Broadband
  High-speed data transmission utilizing a wide range of frequencies to carry multiple signals simultaneously.
• Broadcast radiation
  The ambient level of broadcast and multicast packets circulating on a network segment.
• Broadcast storm
  A cascading network failure caused by broadcast packets endlessly replicating across redundant links.
• Burst mode
  A transmission state where a device sends a continuous block of data without waiting for individual acknowledgments.
• Cablecoalso cable company
  A telecommunications company that primarily operates a coaxial cable network for television and broadband services. Shop talk
• CBDCalso central bank digital currency
  Central bank digital currency, a digital token representing a country's fiat currency.
• CLIalso command line
  A command-line interface is a text-based user interface used to configure and manage network devices and operating systems.
• Cloudalso the cloud
  A network of remote servers hosted on the internet to store, manage, and process data.
• CNA
  Cloud native architecture is a design methodology for building applications specifically to run in distributed cloud environments.
• Connectivity
  The state or capability of devices successfully linking and exchanging data across a network.
• Contention
  A state where multiple devices or users attempt to use the same network resource simultaneously.
• CRUDalso Create Read Update Delete
  The four basic operations required for a complete persistent storage application.
• Digital decayalso bit rot, data rot
  The gradual loss, corruption, or inaccessibility of digital data over time.
• Digital footprintalso digital shadow, cyber footprint
  The traceable record of a user's activities, communications, and data exchanges across networks.
• DOCSIS
  Data Over Cable Service Interface Specification defines how high-speed data is transmitted over coaxial television networks.
• DRCP
  Dynamic Rapid Configuration Protocol is an extension to DHCP designed for faster IP address assignment.
• DSL
  A digital subscriber line is a technology that transmits high-bandwidth data over traditional copper telephone wires.
• dynamic IP address
  A dynamic IP address is a temporary network identifier assigned to a device by a server.
• Eavesdroppingalso passive interception, sniffing
  The unauthorized interception of network traffic or voice communications by a third party.
• End-nodealso host
  An end-node is a device at the edge of a network that originates or receives data.
• Endpoint
  An endpoint is a specific destination or source on a network, often referring to a user device or API URL.
• Erroralso Errored
  A system or process failing and generating a fault state.
• Escape sequence
  A specific string of characters used to send control instructions rather than text data to a terminal or device.
• Exit nodealso exit relay
  The final server in an anonymizing network where traffic emerges onto the public internet.
• Federated
  A network architecture where independent systems interoperate under shared standards.
• Federation
  A group of independent networks or organizations that have established trust to share resources.
• Flappingalso link flapping, route flapping
  A fault condition where a network link or routing path rapidly alternates between online and offline states. Shop talk
• Fork
  A divergence in source code where a copy is developed independently from the original.
• GMPLSalso Generalized Multi-Protocol Label Switching
  Generalized Multi-Protocol Label Switching, a protocol suite for managing network traffic across various transport layers.
• HDSL
  High-bit-rate Digital Subscriber Line is an early broadband protocol for copper wires.
• Inbandalso in-band
  Operating within the primary communication channel rather than on a separate management connection.
• Internet service provideralso ISP, provider
  A company that supplies the physical infrastructure and routing necessary for customers to access the global internet.
• IPLalso IPLC
  An international private line is a dedicated, point-to-point data circuit connecting locations in different countries.
• Keepalivealso keep-alive, heartbeat
  A small, periodic data packet sent between devices to verify that a network connection remains active.
• Lagging
  Experiencing noticeable delay between a user input and the corresponding network response. Shop talk
• Last mile
  The final segment of a telecommunications network that physically reaches the customer premises.
• LPRalso Line Printer Remote, LPD
  The line printer remote protocol used for submitting print jobs over a network.
• Mapper
  A hardware or software component that translates data between different formats, addresses, or protocols.
• Meet-me roomalso MMR
  A secure area in a data center where telecommunications companies physically interconnect their networks.
• Middle mile
  The network segment connecting a provider's core backbone to the local access network.
• Multipointalso point-to-multipoint, P2MP
  A network topology or connection that links three or more distinct endpoints.
• N-facility
  A defined service provided by one layer of a network architecture to the layer immediately above it.
• NDRalso non-delivery receipt, bounce message
  A non-delivery report generated by a mail server when it cannot deliver a message.
• Nonrepudiation
  A security mechanism ensuring that a party cannot deny the authenticity of their signature or the sending of a message.
• OCR
  Software that converts images of typed, handwritten, or printed text into machine-encoded text.
• Offset time
  The delay between a control packet and its corresponding data burst in optical switching.
• Online service provideralso OSP
  A commercial entity that delivers services, content, or infrastructure over the internet.
• Overbuilder
  A telecommunications company that constructs a new network in an area already served by an incumbent operator.
• Patch
  A software update designed to fix bugs, close security vulnerabilities, or improve performance.
• Presentity
  A network entity that provides its current availability and willingness to communicate.
• PSDU
  The physical layer service data unit is the payload of data passed from the MAC sublayer down to the physical layer.
• Push time
  The specific moment or scheduled interval when a server transmits unsolicited data to connected clients.
• QoS
  A set of network mechanisms used to prioritize specific types of traffic over others.
• Quality of servicealso QoS
  The measurable performance of a network service as experienced by the end user or application.
• Remote access
  The ability to connect to and control a computer network or system from an off-site location.
• Router
  A network device that forwards data packets between computer networks.
• RTTalso round-trip time
  The time it takes for a data packet to travel to a destination and back.
• SDSL
  Symmetric Digital Subscriber Line is a broadband technology that offers equal upload and download speeds over copper telephone wires.
• Send
  The action of transmitting data packets, messages, or signals from a local node to a remote destination.
• Siloalso information silo, data silo
  An isolated system or data repository that does not share information with other parts of an organization. Shop talk
• SLAalso Service Level Agreement
  A Service Level Agreement that defines the guaranteed performance metrics between a provider and a client.
• static IP addressalso fixed IP address
  A fixed network address manually assigned to a device, rather than one leased dynamically.
• Sticky
  A configuration or feature that forces a temporary state to remain persistent. Shop talk
• Store and forward
  A routing technique where an entire message or packet is received and verified before being transmitted to the next node.
• Streaming data
  Information that flows continuously from a source to a destination in real time.
• Streaming encoder
  A device or software application that converts raw audio and video into compressed digital formats for live internet broadcast.
• Switch
  A network device that connects devices and forwards data packets to their exact destination.
• TCP/IPalso Internet protocol suite
  Transmission Control Protocol/Internet Protocol is the foundational suite of communication protocols used to interconnect network devices.
• Telemetry
  The automated collection and remote transmission of data from sensors or systems for monitoring and analysis.
• Throwbox
  A stationary relay node used in delay-tolerant networks to store and forward data.
• Transmission timealso serialization delay, packetization delay
  The duration required to push all the bits of a packet or message onto a communications medium.
• Tree-and-branch
  A network topology where a main trunk line splits into progressively smaller distribution lines.
• Turing switch
  A theoretical model used to analyze the logical limits and behavior of network switches.
• Uplinkalso TX
  The communication path originating from a remote device and traveling toward the core network.
• Video conferencealso videoconference, VTC
  A live, visual communication session between two or more participants over a network.

The physical components, connectors, and storage devices that build network infrastructure.

• Acoustic coupler
  An early modem interface that connected a computer to a telephone network by physically cradling a telephone handset.
• Archalso architecture
  The specific hardware architecture or instruction set of a computer processor. Shop talk
• Average access time
  The typical delay between a processor requesting data and the storage device delivering it.
• Average seek time
  The typical time it takes a hard drive actuator arm to position the read and write head over a requested data track.
• Back-to-back connection
  A direct physical link between two identical or similar devices without an intervening network switch.
• Bird's nestalso rat's nest, spaghetti
  An unorganized, tangled mass of cables inside a rack or behind a desk. Shop talk
• Blu-ray Discalso BD
  A high-capacity optical storage medium designed for high-definition video and large data archives.
• Blu-ray drive
  A hardware peripheral that uses a blue-violet laser to read and write high-density optical media.
• BNC connector
  A quick-disconnect radio frequency fitting used for coaxial cable.
• BUDalso big ugly dish
  A large parabolic antenna used to receive C-band satellite television transmissions. Shop talk
• Buttinskyalso butt set, butt-in set
  A rugged, portable telephone handset used by technicians to test lines and monitor circuits. Shop talk
• Camera roll
  The default local storage directory for photos and videos captured on a mobile device.
• Card clash
  An interference error caused when a reader detects multiple radio-frequency identification cards at once. Shop talk
• Cat 5also Category 5, Cat5e
  Category 5 cable, a standard twisted-pair copper cable used for computer networks.
• Coaxial cablealso coax
  A copper transmission line built with a central conductor surrounded by an insulating layer and a braided metallic shield.
• Composite video, blanking, and syncalso CVBS, composite video
  An analog television signal format that combines picture data and synchronization pulses on a single wire.
• Computer architecture
  The fundamental design and organization of a computer system.
• Control keyalso Ctrl
  A modifier key on a computer keyboard used to trigger special commands or shortcuts.
• Conventional memoryalso base memory
  The first 640 kilobytes of system RAM addressable by early IBM-compatible personal computers.
• CVC
  Compact Video Cassette, a historic quarter-inch magnetic tape format for portable video.
• DAT
  Digital Audio Tape, a magnetic tape format used for high-quality audio and data backup.
• Data terminal equipmentalso DTE
  Any end-user device that acts as the source or destination of digital information on a network.
• Datapadalso tablet, MDT
  A portable tablet computer or mobile data terminal. Shop talk
• DCEalso data circuit-terminating equipment, data communications equipment
  Data circuit-terminating equipment provides the physical connection to a network.
• Demarc extensionalso inside wiring, extended demarc
  The physical cabling that connects a service provider's termination point to the customer's networking equipment.
• Deskside serveralso tower server
  A freestanding computer server housed in a tower chassis designed to sit on the floor near a workstation.
• Donglealso hardware key, security token
  A small piece of hardware that plugs into a computer to provide extra functionality or copy protection.
• DPRFP
  Direct Polar Radio Frequency Power is a method of generating RF signals by directly modulating amplitude and phase.
• EIDEalso PATA, Fast ATA
  Extended Integrated Drive Electronics was a standard interface for connecting storage drives.
• Enter keyalso Enter
  A keyboard button used to execute a command, submit data, or create a new line.
• Ethernet cardalso NIC, network adapter
  An expansion board that provides a physical connection between a computer host and a local area network.
• FastWide SCSIalso SCSI-2, Fast/Wide SCSI
  An older parallel storage interface that combined a 16-bit bus with 10 MHz clock speeds.
• Floppy disk drivealso floppy drive, FDD
  A legacy storage device that reads and writes data to removable magnetic disks.
• GBICalso Gigabit Interface Converter
  A Gigabit Interface Converter is a hot-swappable transceiver used to connect network switches to fiber optic or copper cables.
• Hard disk
  A rigid magnetic platter used for non-volatile data storage inside a drive mechanism.
• Hard drivealso HDD
  An electromechanical data storage device containing spinning magnetic platters.
• Hardware node
  A physical device connected to a network that can send, receive, or process data.
• Home computeralso microcomputer
  An older classification for a microcomputer marketed specifically for domestic use rather than business or scientific computing.
• Human interface devicealso HID
  A hardware component that lets a person input data to or receive output from a computer.
• IDEalso ATA, Parallel ATA
  An older interface standard used to connect storage devices to computer motherboards.
• Irisalso waveguide iris, diaphragm
  A metal plate with an opening placed inside a microwave waveguide to alter its impedance and create a resonant cavity.
• Keyboardalso board
  A primary input device consisting of mechanical or membrane switches used to enter alphanumeric data into a computer.
• KVMalso KVM switch
  A hardware device that lets a single keyboard, monitor, and mouse control multiple computers.
• Line card
  A modular printed circuit board that plugs into a telecom switch or router to provide port interfaces.
• LOSalso loss of signal
  Loss of signal, a condition where a receiver no longer detects a valid incoming transmission.
• Lossless junction
  A theoretical or highly efficient connection point where no signal power is dissipated as heat or radiation.
• Mainframe
  A large, high-performance computer designed to process massive volumes of data and support thousands of concurrent users.
• Mass storage
  Non-volatile hardware designed to retain large amounts of data permanently.
• Maximum seek timealso full-stroke seek time
  The longest possible delay for a disk drive head to move between the innermost and outermost tracks.
• MDI
  Medium Dependent Interface, the physical port that connects a network device to the transmission medium.
• MDMalso mux-demux
  Multiplexer-demultiplexer, a device that combines and separates multiple signal streams.
• Multidropalso multipoint
  Describing a network or bus topology where multiple devices share a single communication line.
• Multiprocessoralso SMP
  A computer system containing multiple processing units that share memory and peripherals under a single operating system.
• Network interface cardalso NIC, network adapter
  A hardware component that connects a computer to a computer network.
• Notch
  A cutout at the top edge of a smartphone display that houses the front-facing camera and sensors.
• Old World ROM
  The architecture of early Macintosh computers that stored the operating system toolbox on a physical ROM chip. Shop talk
• P5
  A historic internal codename and slang term for early generations of Intel Pentium processors. Shop talk
• PATAalso Parallel ATA, IDE
  An older computer bus standard for connecting storage devices using parallel signaling.
• Pedestal serveralso tower server
  A standalone server built into an upright tower case rather than a rack-mountable chassis.
• Peripheral devicealso peripheral
  An external piece of hardware connected to a computer to provide input, output, or storage functions.
• Port replicatoralso hub, dongle
  A hardware accessory that provides multiple peripheral connection ports from a single computer interface.
• Post Office boxalso PO box
  A historic piece of test equipment used to measure electrical resistance in telegraph and telephone lines.
• Power-cyclealso hard reset
  To restart a piece of electronic equipment by completely removing and then restoring its electrical power. Shop talk
• Powerwash
  To perform a factory reset on a ChromeOS device by wiping all local user data and settings.
• PS/2also PS/2 port
  A legacy 6-pin mini-DIN connector used to attach keyboards and mice to a computer.
• PSNEXT
  A metric used to evaluate the interference on a single wire pair caused by all other pairs in a multi-pair cable.
• Punchdownalso punch down, insulation-displacement contact
  A mechanical connection method where solid copper wire is forced into a slotted metal clip. Shop talk
• Quadalso star quad
  A cable construction consisting of four individually insulated conductors twisted together.
• Random access memoryalso RAM
  The primary volatile working memory in a computer system where active data and machine code are stored.
• Reperforator
  A historic teletypewriter machine component that punches incoming messages onto paper tape.
• Return key
  A keyboard button used to execute a command or move the cursor to the next line.
• RJalso registered jack
  A standardized physical network interface for connecting telecommunications equipment.
• Rollover cablealso console cable, Yost cable
  A flat console cable where the pinout configuration on one end is completely reversed on the other end.
• RS-232
  A classic standard for serial data transmission between computers and peripheral devices.
• S.M.A.R.T.also SMART
  Self-Monitoring, Analysis and Reporting Technology used to detect impending drive failure.
• Sand battery
  An early, unspillable electrochemical battery used in telegraphy.
• SATAalso Serial ATA
  A common computer bus interface used to connect host bus adapters to mass storage devices.
• Scrubberalso scrub bar, timeline
  A graphical control element used to seek through audio or video media.
• SCSI
  Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices.
• Seek time
  The duration required for a hard drive's read/write head to move to the correct track on the disk platter.
• Shielded twisted pairalso STP
  A copper network cable featuring a conductive foil or braided mesh around its internal wires to block electromagnetic interference.
• SMR
  Shingled Magnetic Recording, a technique that increases hard drive capacity by overlapping data tracks.
• Spudgeralso spludger
  A non-conductive hand tool used for manipulating small wires and opening electronic device casings. Shop talk
• Storagealso mass storage, secondary storage
  The non-volatile components of a computer system that retain digital data when powered off.
• Storage devicealso drive
  A discrete hardware unit designed to record and retrieve digital data.
• Storage mediumalso media
  The physical material that actually retains encoded digital data.
• Streaming tape
  A magnetic storage system that writes data in a continuous flow without stopping between blocks.
• Structured wiringalso structured cabling
  A standardized architecture for building telecommunications cabling infrastructure.
• Superfloppy
  An older, high-capacity magnetic storage disk with the same form factor as a standard floppy.
• Time-domain reflectometeralso TDR
  An electronic test instrument used to locate faults in metallic cables.
• Time-domain reflectometryalso TDR
  The technique of analyzing cable faults by transmitting pulses and measuring their reflections.
• TLBalso translation lookaside buffer
  A translation lookaside buffer is a specialized memory cache that stores recent translations of virtual memory to physical addresses.
• TXalso transmit, transmitter
  The transmission line, port, or signal in a communications link. Shop talk
• UFDalso USB flash drive, thumb drive
  A portable solid-state storage device that connects via a Universal Serial Bus port.
• USB keyalso flash drive, thumb drive
  A compact flash memory drive or hardware security token that plugs into a USB port.
• UTPalso unshielded twisted pair
  Unshielded twisted pair is the standard copper cabling used for Ethernet networks and indoor telephone wiring.
• Watch receiver
  An early, compact telephone earpiece shaped like a pocket watch.
• WideUltra SCSIalso Ultra Wide SCSI, SCSI-3 Fast-20 Wide
  A parallel SCSI interface standard that transfers data at 40 megabytes per second over a 16-bit bus.

The procedural words, frequency bands, and transmission equipment used in radio.

• Anticoherer
  An early radio wave detector whose electrical resistance increases when exposed to radio frequencies.
• Bandalso frequency band
  A specific, contiguous range of frequencies in the electromagnetic spectrum allocated for a particular use.
• Beltpack
  A portable intercom transceiver worn on a user's belt to enable hands-free communication.
• Block upconverteralso BUC
  A transmission component that translates a whole band of lower frequencies to a higher microwave band.
• Botherance
  Irrelevant background chatter heard on a shared emergency radio channel. Shop talk
• Breaker
  A traditional call word used to interrupt ongoing radio traffic and request the channel. Shop talk
• C-bander
  An enthusiast or technician who operates large satellite dish systems to receive unencrypted television feeds. Shop talk
• CDAAalso circularly disposed antenna array, elephant cage
  Circularly disposed antenna array, a large radio direction-finding installation.
• CDDAalso CDAA
  An antenna array consisting of dipoles arranged in a circle.
• Civision
  The application of encryption to television broadcast signals to restrict viewing to authorized receivers.
• Clean feedalso mix-minus
  An audio mix that includes all inputs except for one specific source, usually to prevent feedback.
• Communications satellitealso comsat
  An orbital spacecraft equipped with transponders to receive, amplify, and redirect radio signals back to Earth.
• Cue
  A signal or marker used to trigger a specific action in a broadcast or recording.
• CW
  Continuous Wave, an unmodulated radio signal used primarily for Morse code transmission.
• Dawn chorus
  A type of electromagnetic interference heard on very low frequency radio receivers at sunrise.
• Dead air
  An unintended period of silence in a radio or television broadcast.
• Director
  A passive antenna element placed in front of the driven element to increase forward gain.
• Downleadalso drop cable, feedline
  The cable that connects an elevated antenna to radio equipment at ground level.
• ERPalso equivalent radiated power
  Effective radiated power is the total RF power emitted by an antenna in its main direction of focus.
• FABalso fully advised and briefed
  A radio procedure word used to acknowledge receipt and understanding of a message. Shop talk
• Far fieldalso Fraunhofer region
  The region surrounding an antenna where the electromagnetic field behaves as a predictable plane wave.
• Feedpoint
  The physical location on an antenna where the transmission line connects to transfer radio frequency power.
• Frequency assignment
  The authorization given to a station to use a specific radio frequency under strict technical parameters.
• Frequency bandalso band
  A defined contiguous range of radio frequencies allocated for a specific purpose.
• Ghosting
  A faint, offset duplicate of a television or display image caused by multipath interference or slow panel response.
• HFalso high frequency
  High frequency designates the portion of the radio spectrum between 3 and 30 megahertz.
• Hot microphonealso hot mic, open mic
  A microphone that is actively transmitting or recording without the user actively pressing a button. Shop talk
• Layback
  The process of recording a final, mixed audio track back onto the master video medium.
• MDCalso MDC-1200
  Motorola Data Communications, a signaling protocol used in two-way radio systems.
• MF
  The abbreviation for medium frequency, a radio band ranging from 300 to 3,000 kilohertz.
• Morse codealso CW
  A character encoding scheme that transmits text as a sequence of short and long signal pulses.
• Near fieldalso reactive near field
  The electromagnetic region immediately surrounding an antenna where fields are not yet fully formed into a radiating wave.
• Omnidirectionalalso omni
  An antenna or microphone pattern that radiates or receives equally in all directions horizontally.
• Pizza dishalso minidish
  A small parabolic satellite antenna used for direct-to-home television reception. Shop talk
• Receivealso RX
  To capture and decode an incoming electromagnetic or optical signal.
• Reception
  The quality or act of capturing an incoming radio frequency signal.
• Responsor
  A receiver unit paired with an interrogator to capture and process replies from a transponder.
• Roger
  A voice procedure word meaning the last transmission was received and understood.
• Roger that
  An informal expansion of the standard radio acknowledgment word. Shop talk
• RoIPalso Radio over IP
  A technology that routes two-way radio communications over digital data networks.
• RY
  A standard test pattern used to check teleprinter and radioteletype systems.
• SHF
  Super High Frequency designates the band of radio frequencies between 3 and 30 gigahertz.
• Shortwavealso HF
  Radio transmissions in the high frequency band, between 3 and 30 megahertz, known for their ability to travel global distances.
• Software defined radioalso SDR
  A radio communication system where components typically implemented in hardware are instead implemented by software.
• Soundboardalso mixing console, mixing board
  A control desk used by audio engineers to mix and route multiple audio signals into a single output.
• Squelch
  A circuit function that mutes the audio output of a receiver when no strong signal is present.
• SSBalso Single Sideband
  A radio transmission method that transmits only one sideband of an amplitude-modulated signal.
• Step onalso walk on
  To transmit on a radio frequency while someone else is already transmitting, causing interference. Shop talk
• Super high frequencyalso SHF
  The radio frequency band extending from 3 gigahertz to 30 gigahertz.
• Superband
  A range of frequencies used in cable television systems to carry additional channels.
• Tapeless
  Describes recording or broadcasting workflows that rely entirely on digital files or solid-state media rather than magnetic tape.
• Tapperalso decoherer
  A mechanical device in early wireless telegraphy used to strike a coherer and reset its metal filings.
• Time of origin
  The exact timestamp when a sender officially releases a message for transmission.
• UHFalso Ultra High Frequency
  The radio frequency band spanning from 300 megahertz to 3 gigahertz.
• ULFalso Ultra low frequency
  The band of radio frequencies extending from 300 to 3000 hertz.
• Uplead
  The transmission line connecting a radio transmitter output to an elevated antenna.
• VHFalso very high frequency
  Very high frequency refers to radio waves in the range of 30 to 300 megahertz.
• VLFalso very low frequency
  Very low frequency designates radio waves operating in the 3 to 30 kilohertz range.
• Wabun code
  A telegraphy code used to transmit Japanese kana characters.
• Wilco
  A radio procedure word indicating that a message has been received and its instructions will be followed.
• Wireless telegraphyalso radiotelegraphy, CW
  The historic transmission of text messages via radio waves using Morse code.
• WSPR
  Weak signal propagation reporter is a digital radio protocol designed to probe potential communication paths.
• Zepp antennaalso Zeppelin antenna, end-fed Zepp
  A wire antenna fed at one end by a two-wire parallel transmission line.

The mathematical measurements, modulation schemes, and error rates of data transmission.

• ACI
  A type of signal degradation caused by energy spilling over from a neighboring frequency band.
• ACIR
  A metric defining the ratio of total transmitted power to the interference power affecting a neighboring channel.
• ACLR
  A transmitter measurement comparing the power in the main channel to the power leaking into a neighboring channel.
• ACPR
  A metric that specifies how much of a transmitter's power spreads into adjacent frequency channels.
• ACRRalso Adjacent Channel Rejection
  A receiver's ability to isolate a desired signal from a strong interfering signal on a neighboring frequency.
• ACS
  A receiver measurement defining its ability to process a desired signal while rejecting strong signals on adjacent channels.
• Baseband
  The original frequency range of a transmission signal before it is modulated onto a higher-frequency carrier wave.
• Baudalso baud rate, symbol rate
  A measure of signaling rate representing the number of state changes per second on a communications channel.
• Biotelemetryalso medical telemetry
  The remote measurement and transmission of biological data from a living organism to a receiver.
• Bit interval
  The exact duration of time allocated to transmit a single binary digit over a communication channel.
• Bit stuffing
  The practice of inserting non-information digits into a data stream to break up long sequences.
• Bitratealso Data rate
  The speed at which digital information travels across a network or interface.
• Black noise
  A spectral profile characterized by absolute silence interrupted by occasional random spikes.
• CDD
  A transmission technique that applies distinct delays to signals sent from multiple antennas.
• Celerity
  The historic term for the speed of symbol transmission in a communications channel.
• Compandingalso compression-expansion
  A signal processing technique that compresses a signal before transmission and expands it at the receiver.
• Compandoralso compander
  A device that compresses and then expands an analog signal to improve the signal-to-noise ratio.
• Contraplex
  A transmission method where signals travel in opposite directions simultaneously over the same medium.
• De-emphasis
  A signal processing step that restores the original frequency response of a transmitted signal.
• Demixalso unmix
  The computational process of separating a combined audio or signal feed into its original individual channels.
• Detectionalso demodulation
  The extraction of meaningful information or baseband signals from a modulated carrier wave.
• Directivity
  A measure of how concentrated an antenna's radiated power is in a specific direction.
• Duobinaryalso duobinary encoding, duobinary signaling
  A line coding technique that transmits data at higher speeds by introducing controlled intersymbol interference.
• ELFalso Extremely low frequency
  Extremely low frequency is a band of radio frequencies from 3 to 30 hertz.
• ELFEXT
  Equal-level far-end crosstalk is a metric used to evaluate signal interference in twisted pair cables.
• erlang
  An erlang is a unit of telecommunications traffic measurement representing one hour of continuous voice or data use.
• Escape character
  A specific control code that changes the meaning of the data immediately following it.
• EVM
  A measure used to quantify the performance of a digital radio transmitter or receiver.
• Falsealso falsing
  To incorrectly interpret random noise or interference as a valid signal. Shop talk
• FDR
  A performance metric evaluating the accuracy of format detection in 3G wireless transmissions.
• Forward echo
  A signal reflection that travels in the same direction as the original transmission.
• Frame-alignment recovery time
  The delay before a receiver re-establishes synchronization after detecting a valid frame signal.
• Frequency
  The number of cycles a radio wave or alternating current completes per second.
• Gating
  The process of controlling or blocking a signal based on a specific threshold or timing condition.
• GBRalso guaranteed bitrate
  Guaranteed bitrate, a quality of service parameter for network traffic that requires a minimum constant bandwidth.
• Generation loss
  The degradation of signal quality that occurs each time analog media is copied or transcoded.
• Guard band
  An intentionally unused portion of the radio spectrum placed between active channels.
• Hamming code
  A family of linear error-correcting codes used in digital communication and memory.
• Jitteralso packet delay variation
  The variation in the delay of received packets or the deviation of a digital signal from its precise timing.
• Latency
  The time it takes for a packet of data to travel from its source to its destination.
• Locking shift
  A control character or mechanism that changes the active character set for all subsequent data until reversed.
• Lossfulalso lossy
  Prone to losing data or signal integrity during transmission or processing.
• Lossyalso lossful
  Characterized by the degradation of signal strength or the permanent discarding of data.
• Manchester codingalso phase encoding
  A line coding technique where each data bit includes a voltage transition at its midpoint.
• MBR
  Maximum bitrate, the highest data transfer rate allowed or achievable on a specific connection.
• Neperalso Np
  A logarithmic unit for expressing ratios of physical quantities like voltage or current, based on the natural logarithm.
• OFDMalso Orthogonal Frequency Division Multiplexing
  Orthogonal Frequency Division Multiplexing, a digital transmission method using multiple subcarriers.
• Out-of-bandalso OOB
  Communications or signaling that occurs outside the primary data channel or frequency band.
• Polybius square
  A historic cryptographic grid that maps letters to pairs of numerical coordinates for visual transmission.
• Precursoralso pre-cursor ISI
  An artifact in signal transmission where a portion of a pulse arrives before the main signal energy.
• Propagation constant
  A complex mathematical value that describes how an electromagnetic wave changes as it travels through a medium.
• Propagation mode
  The specific path or physical mechanism by which an electromagnetic wave travels from a transmitter to a receiver.
• Proration
  The allocation of performance parameters across multiple components in a communications circuit.
• REIN
  Repetitive electrical impulse noise is a broadband interference pattern that disrupts digital subscriber lines.
• Retardation
  The slowing down or delay of a transmitted electrical signal over a long circuit.
• Round-trip timealso RTT
  The total time required for a data packet to travel from a source to a destination and for the acknowledgment to return.
• Signal
  An electrical or electromagnetic variation that transmits data or voice from one point to another.
• Signalling event
  A discrete change in the state of a transmission channel used to convey control information or data symbols.
• Spectral gating
  A digital signal processing method that reduces background noise by muting specific frequency bands.
• Subcarrier
  A secondary radio frequency modulated onto a main carrier wave to transmit additional data.
• Submessage
  A distinct, smaller block of data embedded within a larger communications protocol packet or frame.
• Symbol
  The smallest distinct change in a transmission signal that carries data.
• Time difference of arrivalalso TDOA
  A geolocation method that calculates position based on when a signal reaches different receivers.
• Time diversity
  A transmission technique that sends the same data at different times to overcome temporary signal fading.
• Time divisionalso TDM, time-division multiplexing
  The multiplexing of multiple signals over a single channel by assigning each a distinct time slot.
• Time-frequency analysis
  A signal processing method that evaluates spectral properties alongside their temporal occurrence.
• Time-frequency representationalso TFR
  A mathematical view of a signal that maps its amplitude across both time and frequency axes simultaneously.
• Time-hoppingalso TH
  A spread-spectrum transmission technique that varies the exact timing of data bursts using a pseudorandom sequence.
• Transmissible
  Describes a signal or data format that is capable of being successfully sent over a given communications channel.
• Trellisalso trellis diagram
  A time-based graph used to map state transitions in digital encoding schemes.
• VSBalso vestigial sideband
  An amplitude modulation technique where one sideband is partially transmitted.
• Wavelet modulation
  A digital modulation technique that uses orthogonal wavelets as carrier signals.
• Word
  A standardized unit of text length equal to five characters plus one space.

The informal jargon, historic hacker terms, and shop floor idioms of telecom workers.

• Beige box
  A modified telephone equipped with alligator clips for tapping directly into telephone lines. Shop talk
• Blue box
  A historic electronic toll-fraud device used to manipulate long-distance telephone switches. Shop talk
• Brown box
  A historic phreaking device used to bridge two telephone lines into a makeshift party line. Shop talk
• Demon dialingalso war dialing, auto-redial
  The automated, rapid redialing of a busy telephone number to seize a connection the moment it becomes available. Shop talk
• EFF
  The Electronic Frontier Foundation is a nonprofit organization defending civil liberties in the digital world.
• Fleeceware
  A predatory mobile application that charges exorbitant hidden subscription fees for basic functionality. Shop talk
• Gold box
  A historic phreaking device that acts as a line diverter to route incoming calls to a different number. Shop talk
• Hacker
  A skilled computer expert who explores, modifies, or exploits systems and networks.
• Hello girl
  A historic nickname for the female operators who manually routed calls on early switchboards. Shop talk
• Jack inalso plug in
  To physically connect a device to a network using a cable, or to log into a secure digital system. Shop talk
• Loader
  A seller who inflates a computer price by pre-installing expensive, usually pirated or unlicensed software. Shop talk
• Ma Bellalso Bell System
  A historic nickname for the Bell System monopoly that once controlled North American telephone service. Shop talk
• Silver box
  A modified telephone keypad device that generates extra dual-tone multi-frequency signals. Shop talk
• Tech giantalso Big Tech
  A massive, dominant corporation in the information technology or consumer electronics industry. Shop talk
• Time ladyalso speaking clock, POPCORN
  The automated female voice on a telephone speaking clock service. Shop talk
• Truck rollalso dispatch
  The dispatch of a technician in a physical vehicle to a customer site to resolve an issue. Shop talk