Collaboration, Voice & AV terms

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• Acoustic Echo Cancellation (AEC)DSP processing that removes far-end audio picked up by local microphones so remote participants do not hear their own voices.Intermediate
• AES3The professional standard for transmitting two channels of digital audio over balanced 110-ohm cable with XLR connectors.Intermediate
• AES67An AES interoperability standard for high-performance audio over IP using RTP, PTPv2 and common audio formats.Advanced
• Agent StateThe current availability status of a contact center agent, such as Ready, Not Ready, Talking, Reserved or Work.Foundational
• AliasingDistortion created when frequencies above half the sampling rate are sampled and appear as false lower frequencies.Intermediate
• Analog Telephone Adapter (ATA)A small device that connects analog phones or fax machines to an IP telephony system by providing FXS ports.Foundational
• AnnunciatorA CUCM software media resource that plays prerecorded announcements and tones to callers.Intermediate
• As-Built DocumentationFinal drawings and records that show how an AV system was actually installed, including signal flow, rack elevations and labels.Foundational
• Assistive Listening System (ALS)A system that delivers audio directly to people with hearing loss through FM, infrared or induction loop technology.Intermediate
• Audio Clock SynchronizationEnsuring all digital audio devices sample at exactly the same rate from a shared reference to avoid clicks and dropouts.Advanced
• Audio Digital Signal Processor (Audio DSP)A processor that performs digital audio functions such as mixing, EQ, dynamics, AEC, routing and delay in AV systems.Intermediate
• Audio Noise FloorThe level of background noise in a system or room when no intended signal is present.Foundational
• Audio Video Bridging (AVB)A set of IEEE 802.1 standards that provide time-synchronized, low-latency, reserved-bandwidth streaming over Ethernet.Advanced
• Auto Attendant (AA)An automated menu that answers calls and lets callers reach departments or people by pressing keys or speaking names.Foundational
• Auto-RegistrationA CUCM feature that automatically adds unknown phones to the database and assigns them DNs from a configured range.Intermediate
• Automated Alternate Routing (AAR)A CUCM feature that reroutes internal calls over the PSTN when locations-based CAC blocks them for lack of WAN bandwidth.Intermediate
• Automatic Call Distribution (ACD)A system that queues incoming calls and distributes them to available agents according to routing rules.Foundational
• Automatic Mixer (Automixer)A mixer that automatically turns up active microphones and attenuates inactive ones to reduce noise and feedback.Intermediate
• AV Control SystemA system of processors, touch panels and keypads that operates AV devices through IR, RS-232, relays and IP commands.Foundational
• AV Performance VerificationSystematic testing of an installed AV system against standards and design intent, as defined in ANSI/INFOCOMM 10:2013.Intermediate
• AV-over-IP (AVoIP)Distribution of audio and video signals as packets over standard Ethernet networks using encoders and decoders.Intermediate
• AV1A royalty-free video codec from the Alliance for Open Media that is more efficient than H.264 and used by Webex.Intermediate
• Average Handle Time (AHT)A contact center metric equal to talk time plus hold time plus after-call work, averaged across contacts.Foundational
• Back-to-Back User Agent (B2BUA)A SIP element that terminates one call leg as a UAS and originates a separate leg as a UAC, controlling both.Intermediate
• Balanced AudioAudio transmission using two signal conductors of opposite polarity plus a shield, allowing noise rejection at a differential input.Foundational
• BargeA feature that lets a user on a shared line join an active call, using the phone's built-in bridge (Barge) or a conference bridge (cBarge).Intermediate
• Basic Rate Interface (BRI)An ISDN interface with two 64 kbps B channels and one 16 kbps D channel, written 2B+D.Foundational
• Binary Floor Control Protocol (BFCP)A protocol used in SIP video calls to control which participant can send the presentation (content) stream.Advanced
• Bit DepthThe number of bits used to represent each digital audio sample, determining resolution and dynamic range.Foundational
• Boundary MicrophoneA microphone mounted flush with a surface such as a table or ceiling to use the boundary for increased sensitivity.Foundational
• Bring Your Own Meeting (BYOM)A room design in which users run the meeting from their own laptop while using the room's camera, microphones and display.Foundational
• Built-in Bridge (BIB)A conference capability inside Cisco IP phones used for barge and to fork call media to a recording server.Advanced
• Bulk Administration Tool (BAT)A CUCM tool for adding, updating or deleting large numbers of users, phones and other records using CSV files and templates.Foundational
• Business-to-Business Calling (B2B)Voice and video calls between different organizations over the internet, typically using SIP URIs routed through Expressway or SBCs.Intermediate
• Busy Hour Call Attempts (BHCA)The number of call attempts made during the busiest hour of the day, used to size call processing systems.Intermediate
• Busy Lamp Field (BLF)A phone button that shows the real-time state of another line (idle, ringing, busy) and can be used to speed dial it.Foundational
• Call Admission Control (CAC)Mechanisms that limit the number of voice or video calls on a network path so admitted calls keep acceptable quality.Intermediate
• Call AnalyticsA Teams admin center feature that shows per-user detailed information about each call and meeting, including devices and network.Intermediate
• Call Detail Record (CDR)A record generated for each call with details such as calling and called numbers, time, duration and disconnect cause.Foundational
• Call Forward Unregistered (CFUR)A CUCM forwarding setting that routes calls for a DN to an alternate destination, such as its PSTN number, when the device is unregistered.Intermediate
• Call HandlerA Unity Connection object that answers calls, plays greetings, accepts caller input and routes callers to other destinations.Intermediate
• Call ParkA feature that holds a call on a park number so it can be retrieved from any phone by dialing that number.Foundational
• Call PickupA feature that lets a user answer a call ringing on another phone within the same or another pickup group.Foundational
• Call Quality Dashboard (CQD)A Microsoft Teams tool that reports aggregated call and meeting quality across an organization for trend analysis.Intermediate
• Call RecordingCapturing the audio, and sometimes video and screen, of calls for compliance, quality or training purposes.Intermediate
• Call Signaling MarkingMarking SIP, SCCP, H.323 and other call control traffic as CS3 so it gets protected bandwidth without priority queuing.Intermediate
• Caller ID SpoofingFalsifying the calling number or name presented on a call to impersonate a trusted party or hide the caller.Foundational
• Calling and Called Party Transformation PatternCUCM patterns applied at egress or ingress via transformation CSSs to change number presentation, such as localizing +E.164 numbers.Advanced
• Calling Party NormalizationConverting incoming caller ID numbers into globalized +E.164 format so they can be redialed from call history from any location.Advanced
• Calling Search Space (CSS)An ordered list of partitions that a device or line is allowed to search when placing a call, controlling what it can dial.Foundational
• CascadingLinking conference bridges or media nodes together so one meeting spans multiple servers or locations.Advanced
• Centralized Call ProcessingA deployment model in which one CUCM cluster at headquarters controls phones at all branch sites across the WAN.Intermediate
• Certificate Authority Proxy Function (CAPF)A CUCM service that issues, upgrades and deletes Locally Significant Certificates on Cisco IP phones.Advanced
• Certificate Trust List (CTL)A CUCM file of trusted server certificates that enables mixed mode for encrypted and authenticated phone signaling and media.Advanced
• Channel Associated Signaling (CAS)Signaling carried within or tied to each voice channel, such as robbed-bit signaling on a T1.Intermediate
• Chroma SubsamplingReducing color resolution relative to brightness to save bandwidth, written as 4:4:4, 4:2:2 or 4:2:0.Intermediate
• Cisco Collaboration Flex PlanCisco's subscription licensing for collaboration that covers calling, meetings and contact center in the cloud, on premises or hybrid.Foundational
• Cisco Emergency Responder (CER)A Cisco application that tracks phone locations and routes 911 calls with the correct callback and location information.Advanced
• Cisco ExpresswayCisco's collaboration edge gateway that provides secure firewall traversal, remote access, B2B video and interworking.Foundational
• Cisco FinesseCisco's browser-based agent and supervisor desktop for UCCX and UCCE, with gadgets for call control and business apps.Intermediate
• Cisco JabberCisco's legacy unified communications client for chat, presence, voice and video with on-premises CUCM and IM&P.Foundational
• Cisco Meeting Server (CMS)Cisco's on-premises software conferencing platform that hosts audio, video and web meetings in spaces.Intermediate
• Cisco Room KitA family of Cisco video conferencing systems for meeting rooms, combining codec, cameras, microphones and speakers.Foundational
• Cisco Smart LicensingCisco's cloud-based licensing model in which products register to Smart Software Manager and report license consumption.Foundational
• Cisco TelePresence Management Suite (TMS)A legacy Cisco platform for scheduling, managing and monitoring on-premises video endpoints and infrastructure.Intermediate
• Cisco Unified Border Element (CUBE)Cisco's IOS XE session border controller that connects CUCM and Webex Calling to SIP trunk providers and other SIP networks.Intermediate
• Cisco Unified Communications Manager (CUCM)Cisco's on-premises enterprise call control platform that registers endpoints and handles dial plan, features and media resources.Foundational
• Cisco Unified Communications Manager Express (CME)IOS-based call control that runs on Cisco ISR routers for small sites, providing phone registration and PBX features.Intermediate
• Cisco Unified Communications Manager Group (CM Group)An ordered list of up to three CUCM nodes that tells devices which server to register to first and which to use for failover.Intermediate
• Cisco Unified Communications Manager PublisherThe first node in a CUCM cluster, holding the read-write master copy of the configuration database.Intermediate
• Cisco Unified Communications Manager SubscriberA CUCM cluster node that holds a replicated database copy and typically performs call processing, TFTP or music on hold.Intermediate
• Cisco Unified Contact Center Enterprise (UCCE)Cisco's large-scale on-premises contact center with distributed routing, peripheral gateways, CVP and enterprise reporting.Advanced
• Cisco Unified Contact Center Express (UCCX)Cisco's on-premises contact center for small to midsize deployments, integrated with CUCM and offering ACD, IVR and reporting.Intermediate
• Cisco Unified Customer Voice Portal (CVP)Cisco's VXML-based IVR and call control platform used with UCCE for self-service and network queuing.Advanced
• Cisco Unified IM and Presence (IM&P)Cisco's on-premises instant messaging and presence service that integrates with CUCM and uses XMPP for clients.Intermediate
• Cisco Unified Intelligence Center (CUIC)Cisco's web-based reporting platform for contact center real-time and historical reports and dashboards.Intermediate
• Cisco Unified ServiceabilityThe CUCM web interface for activating services, configuring traces, alarms and reporting tools on each node.Foundational
• Cisco Unity Connection (CUC)Cisco's on-premises voicemail, unified messaging and IVR platform that integrates with CUCM and other call control systems.Foundational
• ClearPathCisco's set of media resilience techniques for video, including FEC, rate adaptation and long-term reference frames.Advanced
• Client Matter Code (CMC)A CUCM feature that prompts users for a code on outbound calls so call charges can be billed to clients or projects.Intermediate
• ClippingDistortion that occurs when a signal exceeds the maximum level a device can reproduce, flattening the waveform peaks.Foundational
• Closest Match RoutingThe CUCM rule that selects the pattern matching the fewest possible numbers among all patterns the caller's CSS can reach.Intermediate
• Cloud Connected PSTN (CCP)A Webex Calling PSTN option in which a Cisco-certified provider connects directly to the Webex cloud, with no on-premises gateway.Intermediate
• Cloud Video Interop (CVI)A Microsoft-certified service that lets SIP and H.323 video endpoints join Microsoft Teams meetings.Intermediate
• Clustering over the WANA CUCM deployment model that places cluster nodes at different sites, requiring a maximum of 80 ms round-trip delay between servers.Advanced
• CodecA coder-decoder algorithm that converts analog audio or video to compressed digital form and back.Foundational
• Color TemperatureA measure in kelvin of the color characteristics of light, from warm (lower K) to cool (higher K).Intermediate
• Comfort Noise Generation (CNG)Synthesizing low-level background noise during silence periods so listeners do not think the call has dropped.Intermediate
• Common Channel Signaling (CCS)Signaling sent on a separate dedicated channel shared by all bearer channels, such as the ISDN D channel or SS7.Intermediate
• CompandingCompressing and then expanding signal amplitude, as with mu-law and A-law in G.711, to improve quiet-speech quality.Intermediate
• Compressed Real-time Transport Protocol (cRTP)Header compression that reduces the 40-byte IP/UDP/RTP header to 2 to 4 bytes on slow point-to-point WAN links.Advanced
• Computer Telephony Integration (CTI)Integration between telephony systems and computer applications to control calls and share call data with software.Intermediate
• Condenser MicrophoneA sensitive microphone that uses a charged diaphragm and backplate capacitor, requiring phantom power or a battery.Foundational
• Conditional TrustA switch QoS setting that trusts endpoint markings only when a specific device, such as a Cisco IP phone, is detected via CDP.Intermediate
• Conference BridgeA media resource that mixes audio, and sometimes video, from three or more participants into one conference.Foundational
• Constant-Voltage Audio DistributionA loudspeaker system using 70 V or 100 V lines with transformer taps so many speakers can share one amplifier channel.Intermediate
• Contact Center as a Service (CCaaS)A cloud-delivered contact center platform providing routing, IVR, agent desktop and analytics on a subscription basis.Foundational
• Contact ClosureA simple control method that opens or closes a dry electrical contact, used for screens, lifts, shades and sensors.Foundational
• Contact Service Queue (CSQ)A UCCX queue that holds contacts and selects agents based on resource skills or resource groups.Intermediate
• Content SharingSending a presentation, screen or document as a separate stream in a meeting, wired or wirelessly.Foundational
• Continuous Presence (CP)A conference layout that shows multiple participants on screen at once, such as a grid or active speaker plus thumbnails.Foundational
• Contrast RatioThe ratio of the brightest white to the darkest black in an image, which in a real room is dominated by ambient light.Intermediate
• CTI Route PointA virtual CUCM device that receives calls for an application, which then redirects them, such as a UCCX trigger number.Advanced
• CUBE High AvailabilityBox-to-box or inbox redundancy for CUBE that preserves active calls when the active router fails.Advanced
• CUCM RegionA CUCM setting that defines the maximum audio and video bit rate and preferred codec list for calls within and between regions.Intermediate
• DanteAudinate's widely used audio-over-IP technology that carries many channels of low-latency digital audio over standard Ethernet.Intermediate
• Database ReplicationThe CUCM process that copies configuration data from the publisher to all subscribers so each can process calls independently.Advanced
• Datagram Transport Layer Security for SRTP (DTLS-SRTP)A key exchange method (RFC 5764) that performs a DTLS handshake on the media path to derive SRTP keys.Advanced
• Decibel Unit dBuA decibel unit for audio voltage referenced to 0.775 volts RMS, used for professional line levels.Intermediate
• Delayed Offer (DO)A SIP call flow in which the INVITE has no SDP, so the callee makes the offer in its 200 OK and the caller answers in the ACK.Advanced
• Device MobilityA CUCM feature that applies site-specific settings to phones based on the IP subnet they connect from when roaming between sites.Advanced
• Device PoolA CUCM template of common settings such as CM Group, region, date/time group, location and SRST reference assigned to devices.Foundational
• DHCP Option 150A Cisco-specific DHCP option that gives IP phones a list of TFTP server addresses for downloading configuration files.Foundational
• Dial PeerAn IOS configuration entry that defines a call leg's matching criteria and destination, either POTS (telephony port) or VoIP (IP target).Foundational
• Dial-Peer Group (DPG)A CUBE feature that lets an inbound dial peer explicitly select a list of outbound dial peers, bypassing destination-pattern matching.Advanced
• Dialed Number Analyzer (DNA)A CUCM serviceability tool that simulates digit analysis to show how a dialed number would be routed for a given CSS.Intermediate
• Digit Discard Instructions (DDI)CUCM settings that remove parts of a dialed number, such as PreDot to strip an access code, before sending it to the destination.Intermediate
• Digital Signal 0 (DS0)A single 64 kbps digital voice channel, the basic building block of T1, E1 and ISDN circuits.Foundational
• Digital Signal Processor (DSP)A specialized processor on voice gateways and routers that performs codec conversion, conferencing, transcoding and echo cancellation.Intermediate
• Direct Guest JoinA capability that lets a meeting room device join another platform's meeting as a guest without full interop gateways.Intermediate
• Direct Input Box (DI box)A device that converts unbalanced high-impedance signals to balanced low-impedance mic-level signals for long runs.Intermediate
• Direct Inward Dialing (DID)A carrier service that routes external calls directly to individual internal extensions without an operator.Foundational
• Direct RoutingA Teams Phone PSTN option in which a customer-managed certified SBC connects Teams to a carrier or existing telephony.Intermediate
• Direct-View LED Display (dvLED)A display built from tiled modules of red, green and blue LEDs that emit light directly, with no LCD or backlight.Intermediate
• Directory HandlerA Unity Connection object that lets callers find a user by spelling or speaking a name and then transfers them.Intermediate
• Directory Number (DN)A line number configured on a CUCM device or device profile, associated with a partition and line-level settings.Foundational
• Directory URIA SIP URI such as user@example.com assigned to a CUCM user or DN so callers can dial by alphanumeric address.Intermediate
• Display Image Size for 2D Content in Audiovisual Systems (DISCAS)The ANSI/AVIXA V202.01 standard for calculating display image size based on viewing distance and content type.Advanced
• Domain Name System Service Record (DNS SRV)A DNS record type that maps a service and protocol to the hostname, port, priority and weight of servers that provide it.Intermediate
• Dual-Tone Multi-Frequency (DTMF)Touch-tone signaling in which each keypad digit is a pair of simultaneous tones, one low-group and one high-group frequency.Foundational
• Dynamic Emergency CallingEmergency calling that determines a user's current location from the network so emergency services receive accurate location.Advanced
• Dynamic MicrophoneA rugged microphone that generates signal by moving a coil within a magnetic field, needing no external power.Foundational
• Dynamic RangeThe ratio in decibels between the loudest undistorted level and the noise floor of a system or signal.Intermediate
• Dynamics ProcessingProcessing that changes a signal's level based on its amplitude, including compressors, limiters, expanders and gates.Intermediate
• E-ModelThe ITU-T G.107 transmission planning model that calculates an R-factor from delay, loss and codec impairments to predict call quality.Advanced
• E.164The ITU-T international public telephone numbering plan, with numbers of up to 15 digits beginning with a country code.Foundational
• E.164 Pattern MapA CUBE voice class that lists many number patterns so one dial peer can match all of them.Advanced
• Ear and Mouth Interface (E&M)An analog trunk interface, also called Receive and Transmit, used to tie PBXs together with separate signaling leads.Intermediate
• Early MediaMedia exchanged before a call is answered, such as ringback tones or announcements, typically signaled by 183 Session Progress with SDP.Advanced
• Early Offer (EO)A SIP call flow in which the initial INVITE contains the SDP offer, required by most service provider SIP trunks.Advanced
• Emergency Location Identification Number (ELIN)A DID sent as the calling number on 911 calls so the PSAP can look up the caller's location and call back.Advanced
• Emergency Response Location (ERL)A defined physical area, such as a floor or wing, that an emergency calling system uses to report a caller's location.Advanced
• End-to-End Encryption for Meetings (E2EE)Meeting encryption in which media keys are known only to participants' endpoints, not to the meeting service provider.Advanced
• Enhanced 911 (E911)Emergency calling that delivers the caller's callback number and location to the public safety answering point.Intermediate
• Enhanced Locations Call Admission Control (ELCAC)A CUCM CAC model that represents the network as locations and links with bandwidth so calls across multiple hops are tracked accurately.Advanced
• EqualizationAdjusting the level of specific frequency ranges in an audio signal to correct tonal balance or room problems.Foundational
• ErlangA unit of telephone traffic equal to one circuit continuously occupied for one hour, used for trunk and staffing calculations.Intermediate
• Erlang BA traffic formula that calculates the number of trunks needed for a given busy-hour traffic and blocking probability.Advanced
• Erlang CA queuing formula that estimates how many agents are needed to meet a service level when callers wait rather than being blocked.Advanced
• Expressway ClusterA group of up to six Expressway peers of the same type that share configuration and provide capacity and redundancy.Advanced
• Expressway DNS ZoneAn Expressway zone that routes calls to external domains by looking up DNS SRV and A records for the destination.Intermediate
• Expressway-CThe internal Expressway node that connects to CUCM and other internal systems and acts as the traversal client to Expressway-E.Intermediate
• Expressway-EThe edge Expressway node in the DMZ that faces the internet and acts as the traversal server and TURN relay.Intermediate
• Extended Display Identification Data (EDID)Data a display sends to a source describing its supported resolutions, timings, color formats and audio capabilities.Intermediate
• Extensible Messaging and Presence Protocol (XMPP)An open XML-based protocol for instant messaging and presence, used by Cisco IM and Presence and many chat systems.Intermediate
• Extension Mobility (EM)A CUCM feature that lets users log in to any shared phone and receive their own directory number, speed dials and services.Intermediate
• Extension Mobility Cross Cluster (EMCC)An extension of Extension Mobility that lets users log in to a phone in a different CUCM cluster and register to their home cluster.Advanced
• External Phone Number MaskA per-DN mask that converts an extension into a full external number for caller ID, AAR and CFUR.Foundational
• Far-End Camera Control (FECC)The ability for a participant to pan, tilt and zoom a camera at the remote site during a video call, using H.224/H.281.Advanced
• Fax PassthroughSending fax tones as uncompressed G.711 audio within RTP, with VAD and echo cancellation disabled.Intermediate
• Feature Group Template (FGT)A CUCM template applied during LDAP sync that automatically configures user settings, line and phone services for new users.Intermediate
• FeedbackA howl or squeal caused when loudspeaker sound re-enters a microphone and is amplified repeatedly in a loop.Foundational
• Forced Authorization Code (FAC)A CUCM feature that requires users to enter an authorization code with sufficient level before a route pattern routes the call.Intermediate
• Foreign Exchange Office (FXO)An analog interface that connects to a PSTN line or PBX station port and receives dial tone rather than providing it.Foundational
• Foreign Exchange Station (FXS)An analog interface that supplies dial tone, battery and ringing voltage to connect analog phones, faxes or modems.Foundational
• Frame Rate (fps)The number of complete video images displayed or transmitted per second, such as 30 or 60 frames per second.Foundational
• Frequency ResponseThe range of frequencies a device reproduces and how evenly, usually stated as a range with a tolerance in dB.Foundational
• G.711The ITU-T uncompressed PCM voice codec at 64 kbps, using mu-law or A-law companding and 8 kHz sampling.Foundational
• G.722An ITU-T wideband voice codec at 64 kbps that captures audio from 50 to 7000 Hz for HD voice.Intermediate
• G.729An ITU-T 8 kbps CS-ACELP voice codec widely used to save WAN bandwidth, with annexes A (low complexity) and B (VAD).Foundational
• Gain StructureSetting the gain at each stage of an audio system so signals stay well above the noise floor without clipping.Foundational
• Global Dial Plan Replication (GDPR)An ILS feature that replicates directory URIs, alternate numbers and patterns among CUCM clusters with route strings for routing.Advanced
• Globalized Dial PlanA dial plan design that normalizes all numbers to +E.164 for routing and then localizes them at the egress device.Advanced
• Grade of Service (GoS)The probability that a call is blocked during the busy hour because all circuits are in use, such as P.01 for 1 percent.Intermediate
• Ground LoopAn unwanted current path formed when equipment is grounded at multiple points with different potentials, causing hum.Intermediate
• Group of Pictures (GOP)The sequence of video frames between key frames, made of I-frames, P-frames and optionally B-frames.Intermediate
• H.225The H.323 protocol for call signaling (Q.931-based, TCP 1720) and Registration, Admission and Status (RAS, UDP 1719).Advanced
• H.239The H.323 standard for sending a second video stream, such as presentation content, alongside the main camera video.Advanced
• H.245The H.323 control protocol that exchanges capabilities, determines master/slave and opens logical channels for media.Advanced
• H.264 (AVC)The ITU-T and ISO video compression standard (MPEG-4 Part 10 Advanced Video Coding) used by most conferencing systems.Foundational
• H.265 (HEVC)High Efficiency Video Coding, the successor to H.264 that delivers similar quality at roughly half the bit rate.Intermediate
• H.323An ITU-T umbrella standard for multimedia communication over packet networks, comprising H.225, H.245, RAS and codecs.Intermediate
• H.323 GatekeeperAn optional H.323 component that performs address resolution, admission control, bandwidth management and zone management.Advanced
• HDBaseTA standard that carries uncompressed video, audio, Ethernet, control and power over a single category cable up to 100 m.Intermediate
• HeadroomThe difference in decibels between a system's nominal operating level and the level at which it clips.Foundational
• High Dynamic Range (HDR)Video formats that represent a wider range of brightness and color than standard dynamic range, using 10-bit or higher depth.Intermediate
• Hot DeskingA workspace model where users share desks and log in to a phone or video device to receive their personal settings for the session.Foundational
• Hunt ListAn ordered list of line groups that a CUCM hunt pilot uses to distribute calls.Intermediate
• Hunt PilotA CUCM pattern that, when dialed, distributes calls to members through a hunt list and line groups.Intermediate
• Identity Trust List (ITL)A CUCM file, created by default, that lets phones verify the signature of configuration files and trust CUCM services.Advanced
• Inbound Calling Search SpaceThe CSS assigned to a CUCM gateway or trunk that determines which partitions incoming calls from that device can reach.Intermediate
• Inbound Dial Peer MatchingThe order IOS uses to choose a dial peer for an incoming call leg, ending with default dial peer 0 if nothing matches.Advanced
• Infrared Control (IR)Controlling AV devices by sending modulated infrared light commands, either from a remote or from wired IR emitters.Foundational
• Interactive Connectivity Establishment (ICE)A framework (RFC 8445) that finds the best working media path between endpoints behind NAT using host, reflexive and relay candidates.Advanced
• Interactive Voice Response (IVR)An automated phone system that interacts with callers through recorded prompts, touch-tone input and speech recognition.Foundational
• Intercluster Lookup Service (ILS)A CUCM service that shares cluster information, directory URIs and +E.164 patterns between clusters for automatic intercluster routing.Advanced
• IntercomA CUCM feature providing one-way or two-way speakerphone calls to a designated phone, with a whisper path and auto-answer.Intermediate
• Interdigit Timeout (T302)The CUCM timer (15 seconds by default) that waits for further digits before routing a call when a longer pattern might still match.Intermediate
• Internet Low Bitrate Codec (iLBC)A royalty-free narrowband speech codec designed for robustness to packet loss, at 13.33 or 15.2 kbps.Intermediate
• Internet Telephony Service Provider (ITSP)A carrier that offers PSTN connectivity, phone numbers and calling services to enterprises over SIP trunks.Foundational
• Interview HandlerA Unity Connection object that asks callers a series of recorded questions and saves the answers as a single message.Intermediate
• IP Phone Boot ProcessThe startup sequence in which a Cisco IP phone gets power, learns its voice VLAN, obtains an IP address and TFTP server, downloads its config and registers.Foundational
• IP Phone HardeningDisabling unnecessary features on IP phones, such as PC port access, web access and gratuitous ARP, to reduce attack surface.Intermediate
• IP Private Branch Exchange (IP PBX)A PBX that performs call control over an IP network, registering IP phones and soft clients instead of using TDM line cards.Foundational
• IPMXInternet Protocol Media Experience, an open AV-over-IP standard for pro AV built on SMPTE ST 2110 and AMWA NMOS.Advanced
• Java Telephony API (JTAPI)A Java API used by applications such as UCCX to monitor and control CUCM devices through CTIManager.Advanced
• Jitter BufferA receive buffer that holds and reorders incoming voice packets to play them out at an even rate despite variable arrival times.Intermediate
• JPEG XSAn ISO/IEC 21122 low-latency, lightweight video codec offering visually lossless quality at moderate compression ratios.Advanced
• Key Press Markup Language (KPML)A SIP event package (RFC 4730) that reports dialed digits from an endpoint using SUBSCRIBE and NOTIFY messages.Advanced
• Keystone CorrectionAdjusting a projected image to correct the trapezoidal distortion caused when a projector is not perpendicular to the screen.Foundational
• Lightweight Directory Access Protocol Synchronization (LDAP sync)Importing users from a corporate directory such as Active Directory into CUCM and keeping them updated on a schedule.Intermediate
• Line GroupA CUCM collection of DNs that receive hunted calls using top down, circular, longest idle time or broadcast distribution.Intermediate
• Line LevelThe standard audio signal level between devices, +4 dBu for professional gear and -10 dBV for consumer equipment.Foundational
• Line/Device Calling Search Space ApproachA CUCM design that uses the device CSS for site-specific routing and the line CSS to block destinations a user may not reach.Advanced
• Link Fragmentation and Interleaving (LFI)A QoS tool that fragments large data packets on slow links so small voice packets can be interleaved between fragments.Advanced
• Lip SyncThe alignment of audio with corresponding video so speech matches lip movement.Intermediate
• LobbyA meeting waiting area where participants wait until the host admits them.Foundational
• Local Gateway (LGW)A customer-premises CUBE that connects Webex Calling to an existing PSTN provider or on-premises call control.Intermediate
• Local Media Optimization (LMO)A Teams Direct Routing feature that keeps media local between users and SBCs based on user location and SBC topology.Advanced
• Local Route Group (LRG)A CUCM feature that resolves a placeholder route group to the gateway assigned in the calling device's device pool.Advanced
• Locally Significant Certificate (LSC)A certificate installed on a Cisco IP phone by CAPF, used for TLS when the phone registers in a secure mode.Advanced
• Location-Based Routing (LBR)A Teams Direct Routing feature that restricts toll bypass by routing PSTN calls according to the user's network site.Advanced
• Locations-Based Call Admission ControlCUCM CAC that assigns devices to locations with bandwidth limits and rejects or reroutes calls when a link's budget is exhausted.Intermediate
• Loudspeaker ImpedanceThe nominal AC resistance of a loudspeaker, such as 4 or 8 ohms, which determines the load presented to an amplifier.Foundational
• Mean Opinion Score (MOS)A 1-to-5 rating of perceived voice or video quality, where 5 is excellent and about 4 or higher is toll quality.Foundational
• Media BypassA Teams Direct Routing setting that sends media directly between the Teams client and the SBC instead of through Microsoft relays.Advanced
• Media Flow-ThroughA CUBE mode in which RTP media is terminated and re-originated by CUBE, providing topology hiding and media interworking.Advanced
• Media Gateway Control Protocol (MGCP)A centralized master/slave protocol (UDP 2427) in which a call agent such as CUCM controls voice gateway endpoints.Intermediate
• Media Resource Group (MRG)A CUCM collection of media resources such as conference bridges, transcoders, MTPs, annunciators and MOH servers.Intermediate
• Media Resource Group List (MRGL)An ordered list of media resource groups assigned to a device or device pool to determine which resources it uses.Intermediate
• Media Termination Point (MTP)A CUCM media resource that anchors an RTP stream to bridge mismatches such as DTMF methods, early offer or IPv4/IPv6.Intermediate
• Meet-Me ConferenceA conference that participants join by dialing a pre-assigned meet-me number at a scheduled time.Foundational
• Meeting HijackingUnauthorized entry into an online meeting to disrupt, eavesdrop or share offensive content, also called meeting bombing.Foundational
• Message Waiting Indicator (MWI)A lamp or icon on a phone that lights when the user has new voicemail, controlled by the voicemail system.Foundational
• Microphone ArrayA group of microphone elements whose signals are combined with DSP beamforming to form steerable pickup lobes.Intermediate
• Microphone Level (Mic level)The very low signal voltage produced by microphones, typically around -60 to -40 dBu, which needs a preamplifier.Foundational
• Microsoft Calling PlansA Teams Phone PSTN option in which Microsoft acts as the carrier and provides phone numbers and calling minutes.Foundational
• Microsoft TeamsMicrosoft's collaboration platform for chat, meetings, calling and file collaboration within Microsoft 365.Foundational
• Microsoft Teams PhoneMicrosoft's cloud PBX capability for Teams that provides calling, call control and PSTN connectivity options.Foundational
• Microsoft Teams Rooms (MTR)Certified meeting room systems that run the Teams Rooms app on Windows or Android for one-touch Teams meetings.Foundational
• Mobile and Remote Access (MRA)An Expressway solution that lets Webex App, Jabber and Cisco endpoints use CUCM services from the internet without a VPN.Intermediate
• Multimedia Conferencing MarkingMarking interactive video such as desktop and room conferencing as AF41 under RFC 4594-based designs.Intermediate
• Multipoint Control Unit (MCU)A conference bridge that decodes, mixes and re-encodes audio and video from multiple participants into composite streams.Intermediate
• Music on Hold (MOH)A media resource that streams audio to callers placed on hold, sourced from audio files or a fixed live input.Intermediate
• Native Call QueuingA CUCM hunt pilot feature that queues callers with announcements and music on hold until a line group member is available.Intermediate
• Needs AnalysisThe first phase of an AV project, identifying how clients will use the space, who the users are, and the required functions, budget and constraints.Foundational
• Neighbor ZoneAn Expressway zone that connects to a trusted peer such as CUCM, another Expressway or a gatekeeper on the internal network.Intermediate
• Network Device Interface (NDI)A Vizrt (formerly NewTek) protocol for low-latency video, audio and control over standard IP networks, common in live production.Intermediate
• Nit (cd/m2)A unit of luminance equal to one candela per square meter, used to specify display brightness.Foundational
• Nyquist TheoremThe rule that a signal must be sampled at least twice its highest frequency to be reconstructed accurately.Foundational
• Offer/Answer ModelThe RFC 3264 negotiation in which one side offers SDP media options and the other answers with the chosen subset.Intermediate
• Ohm's LawThe electrical relationship V = I x R, with power P = V x I, used to calculate voltage, current, resistance and power.Foundational
• OmnichannelA contact center approach that handles voice, chat, email, SMS and social interactions with shared routing, context and reporting.Foundational
• One Button to Push (OBTP)A feature that shows a single Join button on a video device for meetings scheduled in its room calendar.Foundational
• One-Way AudioA call fault where only one party can hear the other, usually caused by routing, NAT, firewall or SDP address problems.Intermediate
• Online Voice Routing PolicyA Teams Direct Routing policy assigned to users that contains ordered PSTN usages determining which voice routes they can use.Advanced
• Operator ConnectA Teams Phone PSTN option in which a participating carrier provides and manages SBC connectivity directly to Microsoft.Intermediate
• OpusAn open, royalty-free IETF audio codec (RFC 6716) that adapts from 6 to 510 kbps and from narrowband to fullband.Intermediate
• Outbound Dial Peer MatchingThe IOS process that selects the dial peer for the outgoing leg, using longest destination-pattern match, then preference, then random choice.Advanced
• Overlap SendingSending dialed digits one at a time or in groups to the next system instead of all at once in the initial setup message.Advanced
• Packet Loss Concealment (PLC)Techniques a receiving codec uses to hide missing voice packets by replaying or interpolating audio.Intermediate
• Packet Voice Digital Signal Processor Module (PVDM)A Cisco router module that supplies DSP resources for TDM voice, transcoding, conferencing and media termination.Intermediate
• Packetization DelayThe time a codec waits to collect enough audio samples to fill one voice packet, typically 20 ms.Intermediate
• Pan-Tilt-Zoom Camera (PTZ)A camera that can be remotely moved horizontally (pan), vertically (tilt) and zoomed, often with stored presets.Foundational
• Partition (PT)A logical group of CUCM directory numbers and patterns that share reachability; callers reach it only if their CSS includes it.Foundational
• Personal RoomA permanent, user-specific Webex meeting space reachable by a fixed link, number and video address.Foundational
• Phantom PowerDC voltage, typically +48 V, supplied by a mixer or preamp through balanced microphone cable to power condenser microphones.Foundational
• Phone Security ProfileA CUCM profile that defines device security mode (non-secure, authenticated or encrypted), transport and CAPF settings for phones.Advanced
• Pixel PitchThe center-to-center distance between adjacent pixels on a direct-view LED display, measured in millimeters.Intermediate
• Plain Old Telephone Service (POTS)Basic analog voice service delivered over a copper loop with loop-start signaling, dial tone and ringing voltage.Foundational
• Polar PatternThe directional sensitivity of a microphone or loudspeaker, such as omnidirectional, cardioid, supercardioid or figure-8.Foundational
• Potential Acoustic Gain (PAG)A calculation of how much gain a sound reinforcement system can provide before feedback, compared with needed acoustic gain.Advanced
• Precision RoutingA UCCE routing method that matches calls to agents based on combinations of weighted attributes rather than fixed skill groups.Advanced
• PresenceReal-time availability information about users, such as available, away, in a meeting or on a call.Foundational
• Primary Rate InterfaceAn ISDN digital trunk with 23 B channels plus one D channel on a T1, or 30 B channels plus one D channel on an E1.Foundational
• Priority Queue Provisioning RuleThe Cisco design guideline that strict-priority (LLQ) traffic should not exceed about 33 percent of link capacity.Advanced
• Private Branch Exchange (PBX)A privately owned telephone switch that connects internal extensions and shares a pool of outside lines to the PSTN.Foundational
• Progressive ScanA video format that draws every line of each frame in sequence, denoted by p, as in 1080p.Foundational
• Projection Screen GainA measure of how much light a screen reflects toward the on-axis viewer compared with a matte-white reference of 1.0.Intermediate
• Projector BrightnessThe light output of a projector, specified in ANSI lumens, which determines image visibility in ambient light.Foundational
• Proximity EffectThe increase in low-frequency response that occurs when a directional microphone is very close to the sound source.Intermediate
• Proximity PairingA method in which a client app detects a nearby video device through ultrasound and pairs with it for sharing and control.Intermediate
• PSTN Usage RecordA Teams Direct Routing label that links online voice routing policies to voice routes.Advanced
• Public Switched Telephone Network (PSTN)The worldwide circuit-switched telephone network operated by carriers, reached from enterprise systems through gateways or SIP trunks.Foundational
• Pulse Code Modulation (PCM)The method of digitizing analog audio by sampling, quantizing and encoding the signal as binary values.Foundational
• Q Signaling (QSIG)An ISDN-based inter-PBX signaling protocol that passes features such as calling name and message waiting between systems.Advanced
• Q.931The ITU-T ISDN Layer 3 call control protocol carried on the D channel to set up and tear down calls.Intermediate
• Real-Time Monitoring Tool (RTMT)A client application that monitors CUCM and related servers, displaying performance counters, alerts, logs and traces.Foundational
• Resource AccountA disabled Microsoft Entra ID user object used to give Teams auto attendants and call queues phone numbers and licensing.Intermediate
• Reverberation Time (RT60)The time it takes for sound in a room to decay by 60 dB after the source stops.Intermediate
• RFC 4594 Service ClassesIETF configuration guidelines that map application classes such as VoIP, video, signaling and bulk data to recommended DSCP values.Advanced
• RFC 4733 Telephone EventsAn RTP payload format that carries DTMF digits and other telephony events as named events in the media stream (formerly RFC 2833).Intermediate
• Room CombiningAutomatically reconfiguring audio, video and control when divisible rooms are joined or separated by moveable walls.Intermediate
• RoomOSThe operating system on Cisco collaboration devices such as Room Bar, Room Kit, Board and Desk series.Intermediate
• Route Group (RG)A CUCM collection of gateways or trunks with a distribution algorithm of top-down or circular.Intermediate
• Route List (RL)An ordered list of route groups that a CUCM route pattern points to, used for path selection and failover.Intermediate
• Route Pattern (RP)A CUCM pattern that matches dialed digits and routes the call to a gateway, trunk or route list with optional digit manipulation.Foundational
• Route Pattern WildcardsSpecial characters in CUCM patterns such as X, !, [ ], ., @, # and + that match ranges and lengths of digits.Intermediate
• RS-232 ControlSerial control of AV devices over a DB9 or terminal connection using transmit, receive and ground conductors.Foundational
• RTP Control Protocol (RTCP)The companion protocol to RTP that reports packet loss, jitter and round-trip time for a media session.Intermediate
• Sampling RateThe number of times per second an analog signal is measured when converted to digital, such as 8 kHz or 48 kHz.Foundational
• Scalable Video Coding (SVC)An extension of H.264 that encodes video in layers so receivers can drop layers to match bandwidth or screen size.Advanced
• ScalerA device or function that converts a video signal from one resolution or aspect ratio to another to match a display.Foundational
• SDP Security Descriptions (SDES)A method (RFC 4568) of exchanging SRTP keys in SDP a=crypto attributes within SIP signaling.Advanced
• Search RuleAn Expressway rule that matches a call's alias by pattern and priority and sends the search to a target zone.Advanced
• Selective Forwarding Unit (SFU)A media server that receives streams from participants and forwards selected streams to others without decoding or mixing them.Advanced
• Serial Digital Interface (SDI)A SMPTE standard for uncompressed digital video over 75-ohm coaxial cable with BNC connectors, used in broadcast and live production.Intermediate
• Serialization DelayThe time required to clock a frame's bits onto a physical link, equal to frame size divided by link speed.Intermediate
• Server GroupA CUBE voice class that lists multiple SIP destinations with preferences so one dial peer can target several servers.Advanced
• Service LevelA contact center metric measuring the percentage of contacts answered within a target time, such as 80 percent in 20 seconds.Foundational
• Session Border Controller (SBC)A device at the edge of a VoIP network that secures, normalizes and controls SIP signaling and media between domains.Intermediate
• Session Description Protocol (SDP)A text format (RFC 8866) carried in SIP bodies that describes media streams: IP address, port, codecs and attributes.Intermediate
• Session Management Edition (SME)A CUCM deployment used as a central SIP routing core that aggregates multiple CUCM clusters, PBXs and gateways.Advanced
• Session Traversal Utilities for NAT (STUN)A protocol (RFC 8489) that lets an endpoint discover its public IP and port as seen by a server outside the NAT.Advanced
• Shadow LocationA built-in CUCM location assigned to SIP intercluster trunks so Enhanced Locations CAC can be applied end to end between clusters.Advanced
• Shared CallingA Teams Phone feature that lets users make and receive PSTN calls using a shared number from a resource account.Advanced
• Shared LineA directory number configured on multiple devices so that all ring together and see each other's call states.Foundational
• Signal FlowThe path an audio, video or control signal takes from source through processing and distribution to destination devices.Foundational
• Signal QuantizationThe step in digitization that rounds each sample to the nearest discrete level, introducing small quantization error.Foundational
• Signaling System 7 (SS7)The carrier-grade out-of-band signaling network used between PSTN switches for call setup, routing and number portability.Intermediate
• Significant DigitsA setting on inbound CUCM gateways and trunks that keeps only the rightmost N digits of the called number.Intermediate
• SimulcastSending several independently encoded versions of the same video at different resolutions so a server can forward the right one.Advanced
• Single InboxA Unity Connection feature that synchronizes voicemails into users' Exchange or Microsoft 365 mailboxes alongside email.Intermediate
• Single Number Reach (SNR)A Cisco Unified Mobility feature that rings a user's remote devices such as a mobile phone simultaneously with the desk phone.Intermediate
• Single Sign-On for Collaboration (SSO)Using a SAML or OIDC identity provider so users authenticate once to CUCM, Unity Connection, Expressway or Webex services.Intermediate
• SIP Application Layer Gateway (SIP ALG)A firewall or router feature that inspects and rewrites SIP messages and opens pinholes for RTP media across NAT.Intermediate
• SIP DialogA peer-to-peer SIP relationship between two user agents identified by Call-ID, From tag and To tag that persists for a call.Advanced
• SIP Digest AuthenticationSIP's challenge-response authentication in which a server responds 401 or 407 with a nonce and the client returns a hashed credential.Intermediate
• SIP INVITEThe SIP request method that initiates a session, normally carrying an SDP offer describing the caller's media.Foundational
• SIP Normalization ScriptA Lua script attached to a CUCM SIP trunk that modifies SIP messages for interoperability with other systems.Advanced
• SIP OPTIONS PingPeriodic SIP OPTIONS requests used to monitor whether a SIP trunk peer is reachable and in service.Intermediate
• SIP over TLS (SIPS)Securing SIP signaling with TLS, normally on TCP port 5061, to provide confidentiality, integrity and authentication.Intermediate
• SIP ProfileA rule set that adds, modifies or removes SIP headers and SDP lines on CUBE, or a set of SIP parameters on CUCM trunks and phones.Advanced
• SIP Proxy ServerA SIP intermediary that receives requests and forwards them toward the destination, applying routing and policy.Intermediate
• SIP Recording (SIPREC)The IETF standard (RFC 7866) in which an SBC forks call media and metadata to a recording server using SIP.Advanced
• SIP Redirect ServerA SIP server that answers a request with a 3xx response telling the caller where to resend it rather than forwarding it.Intermediate
• SIP RegistrarA SIP server that accepts REGISTER requests and binds a user's address of record to the device's current contact address.Foundational
• SIP Registration HijackingAn attack in which an adversary sends a forged REGISTER to bind a victim's SIP address to the attacker's device.Advanced
• SIP Reliable Provisional Responses (PRACK)The RFC 3262 extension that makes 1xx responses reliable by requiring a PRACK acknowledgment, signaled by the 100rel option tag.Advanced
• SIP Response CodesThree-digit SIP status codes grouped into classes 1xx provisional, 2xx success, 3xx redirection, 4xx client error, 5xx server and 6xx global failure.Intermediate
• SIP Route PatternA CUCM pattern that routes calls by domain or IP address, or by ILS route string, to a SIP trunk.Advanced
• SIP ScanningAutomated probing of the internet or a network for SIP devices and extensions, often as reconnaissance for toll fraud.Intermediate
• SIP TrunkA SIP signaling connection between two call control systems or between an enterprise and a service provider.Foundational
• SIP URIA SIP address in the form sip:user@host that identifies a user, device or service, similar to an email address.Foundational
• SIP User Agent (UA)A SIP endpoint that originates requests as a user agent client (UAC) and answers them as a user agent server (UAS).Foundational
• Skinny Client Control Protocol (SCCP)A Cisco proprietary stimulus protocol (TCP 2000, 2443 secure) used by older Cisco phones and by media resources to talk to CUCM.Intermediate
• SMPTE ST 2110A suite of SMPTE standards for carrying separate video, audio and ancillary data streams over IP networks in professional media.Advanced
• Software Defined Video over Ethernet (SDVoE)An AV-over-IP platform from the SDVoE Alliance that uses 10 Gigabit Ethernet for very low latency, high-quality video.Advanced
• Sound MaskingAdding engineered background sound to a space to reduce speech intelligibility and distractions, improving privacy.Intermediate
• Sound Pressure Level (SPL)The acoustic pressure of a sound expressed in decibels relative to 20 micropascals, the threshold of human hearing.Foundational
• Spam over Internet Telephony (SPIT)Unsolicited bulk VoIP calls or messages, the telephony equivalent of email spam.Intermediate
• Speaker LevelThe high-power amplified signal sent from a power amplifier to loudspeakers, from a few volts to tens of volts.Foundational
• Speaker TrackingCamera automation that uses microphone arrays and face detection to frame the active speaker automatically.Intermediate
• Speech Transmission Index (STI)A 0-to-1 objective measure of speech intelligibility through a sound system and room, defined in IEC 60268-16.Advanced
• STIR/SHAKENStandards that let carriers cryptographically sign and verify caller ID on SIP calls to combat spoofed robocalls.Intermediate
• Survivable Branch Appliance (SBA)A component on a Teams Direct Routing SBC that lets Teams clients keep making PSTN calls when the branch loses connection to Microsoft.Advanced
• Survivable Remote Site Telephony (SRST)A Cisco router feature that lets branch phones register locally and keep basic calling when they lose contact with CUCM.Intermediate
• T.38The ITU-T standard for real-time fax relay over IP that converts fax signals into data packets rather than audio.Intermediate
• Tail-End Hop-Off (TEHO)Routing a PSTN call over the private WAN to the gateway closest to the destination so it leaves as a local or cheaper call.Advanced
• Teams Admin Center (TAC)The Microsoft web portal for administering Teams users, policies, phone numbers, devices, meetings and voice features.Foundational
• Teams Auto AttendantA Teams Phone feature that answers calls with menus, directory search and business-hour routing using a resource account.Intermediate
• Teams Call QueueA Teams Phone feature that holds callers with music and greetings and distributes them to agents using routing methods.Intermediate
• Teams Calling PolicyA Teams policy that controls calling features such as private calls, call forwarding, simultaneous ring, voicemail and delegation.Intermediate
• Teams Cloud VoicemailThe Teams voicemail service that stores messages in users' Exchange Online mailboxes with optional transcription.Foundational
• Teams Dial PlanA Teams policy containing normalization rules that translate user-dialed strings into E.164 numbers.Intermediate
• Teams Media Port RangesMicrosoft's recommended Teams client source ports and DSCP values for audio, video and screen sharing QoS.Intermediate
• Teams Phone MobileA Teams Phone option where a user's mobile carrier SIM number is also their Teams phone number.Intermediate
• Telephony Class of ServiceIn telephony, the set of destinations and features a user or device is allowed to reach, enforced with partitions and CSSs.Foundational
• Telephony Denial of Service (TDoS)An attack that floods a phone system or number with calls to make it unavailable to legitimate callers.Intermediate
• TelePresenceHigh-quality video conferencing designed to create the feeling of being in the same room, often with life-size images.Foundational
• Three-Point LightingA lighting method using key, fill and back lights to illuminate a subject evenly and separate it from the background.Foundational
• Throw RatioA projector's throw distance divided by the image width, used to determine where to mount the projector.Foundational
• Tie LineA dedicated private trunk that connects two PBXs or call control systems at different sites.Foundational
• Time-Division Multiplexing (TDM)A technique that carries multiple channels on one circuit by giving each a fixed, repeating time slot.Foundational
• Time-of-Day RoutingA CUCM feature that makes partitions active only during defined time schedules, changing call routing by time and date.Intermediate
• Toll FraudUnauthorized use of a telephony system to place calls, usually expensive international or premium-rate calls, at the owner's expense.Intermediate
• Topology HidingConcealing internal IP addresses, hostnames and network structure from external parties by rewriting signaling and relaying media.Intermediate
• Transcoder (XCODE)A DSP-based media resource that converts a media stream from one codec to another when endpoints share no common codec.Intermediate
• TransformAn Expressway rule that rewrites a dialed alias before search rules are applied, such as adding a domain to a bare number.Advanced
• Translation Pattern (TP)A CUCM pattern that manipulates calling or called digits and then re-routes the call using its own CSS.Intermediate
• Traversal Using Relays around NAT (TURN)A protocol (RFC 8656) in which a server relays media for endpoints that cannot connect directly through NAT or firewalls.Advanced
• Traversal ZoneAn Expressway zone that links Expressway-C (client) and Expressway-E (server) through the firewall for signaling and media.Intermediate
• Trust Verification Service (TVS)A CUCM service that phones contact to verify certificates not found in their ITL file.Advanced
• UC Service ProfileA CUCM configuration assigned to users that tells clients such as Webex App or Jabber where to find voicemail, conferencing, directory and IM servers.Intermediate
• Unbalanced AudioAudio transmission using one signal conductor and a shield that also serves as the return, making it susceptible to noise.Foundational
• Unified Communications (UC)The integration of voice, video, messaging, presence, conferencing and voicemail into a consistent user experience.Foundational
• Unified Communications as a Service (UCaaS)Cloud-delivered unified communications, including calling, meetings and messaging, provided by a vendor on a subscription basis.Foundational
• Unified Messaging (UM)Integrating voicemail, email and fax into a single mailbox or interface accessible from multiple devices.Foundational
• Unity Connection Call Routing RulesOrdered rules in Unity Connection that decide where direct and forwarded calls are sent based on caller, called number and schedule.Advanced
• Unity Connection Class of ServiceA Unity Connection setting that defines which features and limits apply to users, such as message length and licensed features.Intermediate
• Unity Connection Search SpaceAn ordered list of Unity Connection partitions that defines which users, handlers and extensions an object can reach.Advanced
• Urgent PriorityA CUCM pattern setting that routes a call immediately on match instead of waiting for interdigit timeout on overlapping patterns.Intermediate
• USB Video Class (UVC)The USB standard that lets cameras work with computers without custom drivers, used by conferencing cameras and video bars.Intermediate
• User TemplateA Unity Connection template that supplies default settings such as COS, schedule, time zone and greetings when users are created.Intermediate
• Video Bandwidth ProvisioningSizing network capacity for video by adding overhead, typically about 20 percent, to the configured video call rate.Advanced
• Video CompressionReducing video data by removing spatial and temporal redundancy and perceptually less important detail.Foundational
• Video ConferencingReal-time two-way or multipoint audio and video communication between participants in different locations.Foundational
• Video Matrix SwitcherA device that routes any of multiple video inputs to any of multiple outputs, often with scaling and EDID management.Foundational
• Video WallMultiple displays or LED modules tiled together and driven by a processor to appear as one large image.Foundational
• Voice Activity Detection (VAD)A codec feature that stops sending packets during silence to save bandwidth, also called silence suppression.Intermediate
• Voice Class CodecAn IOS list of preferred codecs that a dial peer offers or accepts, in order of preference.Intermediate
• Voice Class TenantA CUBE configuration block that groups SIP settings such as registrar, credentials and bindings for a specific trunk or customer.Advanced
• Voice Class URIA CUBE voice class that matches SIP URIs by host, user or pattern for inbound dial-peer selection.Advanced
• Voice Extensible Markup Language (VoiceXML)A W3C XML language for defining voice dialogs, used by IVR platforms for prompts, speech recognition and DTMF input.Advanced
• Voice GatewayA device that converts between IP telephony signaling and media and TDM or analog interfaces such as PRI, FXO and FXS.Foundational
• Voice RouteA Teams Direct Routing object containing a number pattern regex, one or more SBCs and associated PSTN usages.Advanced
• Voice Translation ProfileAn IOS object that groups voice translation rules for calling, called and redirect numbers and is applied to dial peers or trunks.Intermediate
• Voice Translation RuleAn IOS regular-expression rule that rewrites calling or called numbers, applied through a translation profile on dial peers or voice ports.Intermediate
• Voice-Activated Switching (VAS)A conference mode that shows the current active speaker full screen and switches as different participants speak.Foundational
• Voicemail PilotThe number in CUCM that routes calls to the voicemail system when users press Messages or calls forward to voicemail.Intermediate
• Voicemail PIN SecurityPolicies that enforce strong voicemail PINs and lockouts to prevent unauthorized mailbox access and toll fraud.Intermediate
• Voicemail ProfileA CUCM setting that ties a directory number to a voicemail pilot and optional voicemail box mask.Intermediate
• VoIP Bandwidth CalculationComputing per-call bandwidth from codec payload, packetization period and Layer 2, IP, UDP and RTP header overhead.Intermediate
• VoIP EavesdroppingIntercepting voice or video traffic, for example by capturing unencrypted RTP and reconstructing the audio.Intermediate
• VoIP NAT TraversalTechniques that allow SIP signaling and RTP media to work across NAT devices that rewrite IP addresses and ports.Intermediate
• VP8A royalty-free video codec from Google that, along with H.264, is mandatory to implement in WebRTC.Intermediate
• Web Real-Time Communication (WebRTC)A W3C and IETF framework that lets browsers and apps exchange real-time audio, video and data without plugins.Intermediate
• Webex AppCisco's client for messaging, meetings, calling and whiteboarding on desktop, mobile and web (formerly Webex Teams).Foundational
• Webex CallingCisco's multi-tenant cloud calling service (UCaaS) that provides enterprise PBX features from the Webex cloud.Foundational
• Webex Calling Call QueueA Webex Calling feature that holds callers in a queue with announcements and distributes calls to agents.Intermediate
• Webex Calling Dedicated InstanceA Webex Calling option that provides a private, dedicated CUCM-based calling environment hosted in the Webex cloud.Intermediate
• Webex Calling Dial PlanAn organization-level Webex Calling configuration that routes dial patterns to trunks or route groups instead of the location's PSTN.Advanced
• Webex Calling LocationA Control Hub object representing a physical site that holds its address, PSTN connection, numbers, emergency settings and dial plan.Intermediate
• Webex Calling Trunk and Route GroupControl Hub constructs that connect Webex Calling to premises gateways and group multiple trunks for redundancy.Advanced
• Webex Cloud-Connected UC (CCUC)A Webex service that connects on-premises CUCM clusters to Control Hub for analytics, certificate and upgrade management.Advanced
• Webex Contact Center (Webex CC)Cisco's cloud contact center (CCaaS) offering omnichannel routing, IVR flows, agent desktop and analytics.Intermediate
• Webex Contact Center Flow DesignerThe Webex Contact Center visual tool for building IVR, routing and digital channel flows with drag-and-drop activities.Intermediate
• Webex Control HubThe web-based management portal for Webex services, users, devices, licenses, analytics and troubleshooting.Foundational
• Webex Directory ConnectorAn on-premises Windows application that synchronizes Active Directory users and groups into the Webex cloud.Intermediate
• Webex Edge AudioA Webex service that routes meeting call-in and callback audio over the enterprise's IP network and Expressway instead of the PSTN.Advanced
• Webex Edge ConnectA dedicated network interconnect between an enterprise and the Webex cloud through an exchange such as Equinix.Advanced
• Webex Hybrid Calendar ServiceA Webex service that connects Microsoft 365, Exchange or Google calendars to Webex for meeting scheduling and One Button to Push.Intermediate
• Webex Media PortsThe network ports Webex clients and devices use for media, preferring UDP 5004 and falling back to TCP or TLS 443.Intermediate
• Webex MeetingsCisco's cloud video conferencing service for scheduled and personal-room meetings, webinars and events.Foundational
• Webex Video MeshOn-premises Webex media nodes that keep meeting media local to the enterprise and cascade to the cloud only when needed.Advanced
• Wideband Audio (HD Voice)Voice transmission covering about 50 Hz to 7 kHz or more, roughly double the bandwidth of traditional narrowband telephony.Foundational
• Wireless Presentation SystemA system that lets users share laptop or mobile screens to a room display without cables, using a dongle or app.Foundational
• Workforce Optimization (WFO)A suite of contact center tools for workforce management, quality management, call recording and performance analytics.Intermediate