PBX AND VOIP GLOSSARY

Navigating through all of the technical terms associated with phone systems, VoIP, and communications can be confusing. Don’t worry, we’ve got you covered. We hope this PBX & VoIP dictionary will help you navigate the jungle of telecom jargon.

ACD

Automatic Call Distribution. A device, system, or feature that automatically routes your incoming calls to a specific group of phones.

Agent Login

A phone function that allows your agents to log into and out of a call queue at the start and end of their shift. When logged out, agents’ calls are automatically forwarded onto the next available agent.

Analog Phone

A typical phone that transmits voice data by converting it into electronic pulses. Analog technology has been around for decades and relies exclusively on copper wire telephone lines and RJ-11 connections. Analog phones are typically inexpensive but offer limited features and require extensive hardware to support large systems.

Automatic Number Identification

Automatic Number Identification. A feature that automatically determines the phone number of a caller, usually through the Digital Tone Multi Frequency (DTMF) tones that accompany the call.

Application Programming Interface

Application Programming Interface. Tools or routines used to build software that integrates two applications together. Hosted voice and unified communications providers generally provide integrations between their platforms and applications like Salesforce, or other common CRMs and ERP systems.

Asterisk

Open-source software that allows a computer to operate like a Private Branch Exchange (PBX). Connected telephones can make calls to one another and connect to other communications services like the Public Switched Telephone Network (PSTN) and Voice over Internet Protocol (VoIP) networks.

ATA

Analog Telephone Adapter. A converter box that converts voice signals from your analog phone or fax so those signals can be transmitted through a VoIP network.

Auto Attendant

The automatic system that answers inbound calls with a pre-recorded message and menu options (“Press 1 or sales, 2 for support” etc.).

B Channel

Bearer Channel. A channel provided in a Basic Rate Interface (BRI). A B-Channel carries data, voice, and other signals. It has a dedicated Bandwidth of 64 Kbps, although a BRI can offer up to two B-Channels in a single telephone line.

Backbone

The part of a network infrastructure that carries data gathered from smaller lines, like LANs or subnetworks.

Bandwidth

The measure of data that can be sent/received over time, usually measured as bits per second (mb/s or bps). Essentially, this refers to how fast your Internet connection is and how much information can pass through at a time. Upload and download rates will usually have different values.

Barge in

A phone feature that allows you to join in on an existing phone call, usually to assist in answering questions, clearing up information, or closing a sale. In barge mode, both the customer and the agent can hear you, creating a three-way conversation. Barge is one of three possible call-monitoring modes (see Spy and Whisper for the other two).

BLI

Busy Lamp Indicator. A light on a phone that shows when a line is in use.

BRI

Basic Rate Interface. An Integrated Services Digital Network (ISDN) line that delivers up to two Bearer Channels (B-Channels) and one Data Channel (D-Channel) over an ordinary telephone line. The BRI is intended primarily for home and small business use, while larger networks are usually supported using a Primary Rate Interface (PRI).

BYOD

Bring Your Own Device. The trend where employees increasingly access company applications, data, records, and programs via their personally owned mobile devices.

Cable Internet

Internet connectivity delivered through your cable modem or gateway device, running over your cable connection.

Call Analytics

Management tools offered by some VoIP providers. Call analytics allow you to view your macro and micro phone traffic patterns and sort the collected data into usable call reports. These can include interactive reports, charts, tables, maps, and graphs.

Call Center

A location equipped with a contact center system and several agent stations (typically equipped with a desktop computer and phone) where your employees can answer a high volume of customer calls.

Call Hunting

A call feature that allows inbound calls to bypass busy signals on a set group of phones (see Ring Group).

Call Logs

Call reports that include dates, times, duration, users, and extensions dialed.

Call Monitoring

A feature that enables you to monitor a current call on lines in your system without interrupting the call. Call monitoring features typically offer three modes: Barge, Spy, and Whisper.

Call Queue

A feature that uses an Automatic Call Distributor (ACD) to place incoming calls in a prioritized order, or queue, and assigning that order to a specific phone line (referred to as an “agent”) or group of lines.

Call Recording

The ability to record some or all of the calls to and from your phones. Recordings are stored in the cloud so they can be accessed from anywhere.

Call Reports

Reports that allow you to review statistics derived from your phone system usage, including call count, time of day, call duration, caller geography, call information, etc.

CAT5 / CAT5e / CAT6

A cat 5—or category 5 (5e, or 6)—is an Ethernet cable, or cabling used to support computer networks. It can transmit video and telephony signals in addition to standard computer data. The cat 5 is usually the bare minimum required for Hosted VoIP. The number designation describes how much data the cable can handle: the cat 5 tops out at 10/100 Mbps speeds at up to 100 MHz bandwidth, the cat 5e at 1000 Mbps speeds, and cat 6 at 10 gigabits for up to 250 MHz. The cable has RJ45 tips on both ends.

Call Detail Record

Also known as call reports. Reports that allow you to review statistics derived from your phone system usage, including call count, time of day, call duration, caller geography, call information, etc.

Centrex

A service that provides like a private branch exchange (PBX), only the equipment is located at the phone service provider’s office instead of at the customer’s location.

CLEC

Competitive Local Exchange Carrier. New carriers doing business after the 1996 Telecommunication Act. The Telecommunications Act was passed to promote competition between new CLEC competitors and established incumbent local exchange carriers (see ILEC).

Client

A software application installed on your computer so you can make and receive phone calls via the Internet.

Cloud

Services and information that are hosted remotely and delivered over the Internet are considered to be “in the cloud.”

Cloud Communications

A service where the voice and data communication equipment is hosted by a third party at a remote location and accessed through an Internet connection. This usually reduces cost and places the burden of maintenance on the service provider instead of the customer.

Cloud PBX

A cloud PBX is a telephony solution completely managed, stored, and maintained over the Internet through cloud computing technology, rather than through hardware owned and maintained by the end-user at the user’s location.

CO

Central Office. In telecommunications, this is where phone service subscribers’ lines pipe into the area’s local loop. Switches located in the central office can then connect calls locally or to a long-distance carrier’s phone office.

Codec

Software or hardware used to encode a data signal or data stream (including a voice or video stream) for easy transmission and then decoding at the receiving end of the signal in the form most appropriate for listening or viewing.

Conference Bridge

A feature that allows multiple callers to dial in to a virtual meeting room where each participant can be heard.

Conferencing

Unlike conference bridging, this feature allows a caller to add a second outgoing call to his or her existing call, enabling all three users to communicate.

Contact Center

A sophisticated telecommunications system you’d use to manage and route a large volume of calls from customers. You usually employ a contact center solution to run a call center.

Corporate Directory

An on-handset directory that allows callers to search for a given user by name and then dial that user directly. The corporate directory provides searchable contact matching by integrating with your existing LDAP (Lightweight Directory Access Protocol) directory, or with external catalogs like Active Directory.

CPE

Customer Premise Equipment. Phone system equipment that is located at the customer’s office location.

CRM

Customer Relationship Management. Software that organizes, automates, and synchronizes a company’s marketing, sales, and customer service to manage interactions with current and prospective customers.

CSR

Customer Service Record. The service record your current provider maintains about your account. The CSR usually includes important information like services, locations, lines, and other details.

CTI

Computer Telephony Integration. Systems that allow you to control the flow of incoming and outgoing communications—usually phone calls, but can also include faxes and Internet messages—with your computer.

Custom Greetings/Messages

Recordings that can be uploaded and used at any point during a dial plan, or as a prompt to leave a voicemail message. Custom greetings and custom messages can be played to all callers, only those reaching a particular department, or even to specific VIP callers based on their incoming number.

Custom Hold Music

Recorded music used to give your callers something to listen to while they wait on hold. With many VoIP solutions, hold music playlists can be uploaded and personalized. Custom messages can also be played along with hold music.

Custom Schedules

A feature that allows you to create time-based call routing plans. This option is most commonly used by business owners to create schedules for open/closed office hours, or to schedule specific call routing for holidays and special events.

D-Channel

Data Channel. A channel that comes as part of a Basic Rate Interface (BRI). The D-Channel transmits controlling and signaling data as packets. A single telephone line can offer a dedicated D-Channel bandwidth of 16 Kbps.

Data Center

A remote facility that houses your company’s dedicated servers and data storages. Data centers provide a home for your critical systems and processes, often processing and disseminating data and telecommunication services across multiple locations. Reliability and security are a priority for datacenter clients, requiring these facilities to install backup power supplies, data connection redundancies, environmental controls, and other security measures.

Data Transfer Rate

How quickly data travels from one point to another.

Demarc

The physical point of demarcation in a phone system. The service becomes the provider’s responsibility up to the demarc point, and the customer’s responsibility after the demarc point.

DHCP

Dynamic Host Configuration Protocol. A protocol that allows a router or gateway to automatically assign an IP address to a device as soon as it gets plugged into the LAN.

Dial by Extension

This phone feature lets you call an extension inside your phone system by dialing a few digits (between three and six) instead of dialing a complete 10-digit phone number.

Dial by Name

A phone system feature that allows you to dial an employee’s extension using only their name instead of their phone number.

Dial Plan

A dial plan lets you create a specific call path within your phone system. Calling a certain number will trigger that routing plan, usually on a busy/always/no answer basis. You can configure a dial plan to automatically reroute calls to other targets besides the phone associated with the number—like an auto attendant, menu, custom greeting, call queue, voicemail box, cell phone number, etc.).

Dial-by-Name Directory

An option that lets you find an employee’s number or extension using only their name. The directory is accessible through an IP phone or the Online User Portal.

DID

Direct Inward Dialing. The 7-10 digit phone number assigned to a specific extension. DIDs are accessed directly and don’t require callers to dial a central or main number.

Digital Phone

A phone that processes and sends your audio signals digitally instead of through analog technology. Unlike IP phones, which send and receive calls via a data connection, a digital phone uses traditional phone lines.

Direct Outward Dialing

With direct outward dialing, users are able to make outbound calls to anyone outside of their PBX by dialing the standard format for local, national, or international numbers. Under system settings you can even set a default area code to eliminate the frequent dialing of that code.

DNS

Domain Name Service. A service that converts website addresses or domain names into Internet Protocol (IP) addresses.

DS0

Digital Signal 0. The basic digital transmission rate that is the basis for the T-Carrier and E-Carrier telecommunications systems in North America, Europe, and Japan. A DS0 channel is designed to transmit digital voice data at a rate of 64 Kbps.

DSL – ADSL

Digital Subscriber Line / Asymmetric Digital Subscriber Line. DSL is a term for the service or technology that delivers broadband information over copper telephone wire. The most common version of DSL is ADSL, which means that the speed of data sent or received can vary.

DTMF

Dual Tone Multi-Frequency. The tones generated by pressing the keypads on your telephone. Each keypad creates two tones, one from a high-frequency group, the other from a low-frequency one. The two-tone combinations are used to identify the dialed number.

Dynamic IP Address

An IP address that changes over time. Most devices use dynamic IP addresses. They can change every time you log onto your computer, or every few days, weeks, or months, depending on your Internet Service Provider (ISP). Addresses are automatically assigned by a DHCP server.

E-Carrier System

A digital data transmission system used in Europe, similar to the T-Carrier System used by telecommunications carriers in North America and Japan. The E-Carrier system relies on Digital Signal 0 (DS0) as its basic unit. The E1 line provides you with access to multiple DS0 channels for a total capacity of 2.048 Mbits per second.

E1

A high-speed digital transmission line used in the European E-Carrier System. The E1 is similar to the North American T1 line.

E911 Service

“Enhanced 911”; A service that directs 911 calls across a VoIP network to the closest PSAP (Public-Safety Answering Point) and automatically provides accurate, specific location information to emergency dispatchers and responders.

Escape from Call Queue

A feature that lets you escape from a call queue, usually redirecting you to another department, operator, extension, or auto attendant.

Ethernet

A widely used computer networking technology that connects your computers, switches, and routers to create a Local Area Network (LAN) where all the devices can communicate with each other.

Exchange Area

The option available in a Private Branch Exchange (PBX) that allows you to register calls within your system as local, enabling you to dial a shorter extension rather than a complete 10-digit phone number.

Extension Dialing

A feature that allows you to reach an internal phone line (or extension), one that is within your Private Branch Exchange (PBX), by dialing a shorter set of digits instead of a typical 10-digit number.

Extensions

A 3, 4, 5, or 6-digit number assigned to all your internal/on-net extensions. Extensions are usually accessible from a central/main number directed to an auto attendant.

Fax to Email

The ability to use your email account and the Internet, in place of a fax machine and phone lines (traditional fax), to transmit and receive faxes.

Find Me/Follow Me

An advanced call forward preset that lets you direct calls made to your extension to a predetermined list of secondary numbers so you can still be accessible even when away from your desk phone. You’re free to direct calls to another internal extension, an external number (like a cell phone or home number), a call queue, or a voicemail box. Calls can be configured to ring multiple phones simultaneously or in a specific order.

FiOS

Fiber Optic Service. A bundled Internet, TV, and telephone service created and trademarked by Verizon Communications and delivered via fiber optic cables. FiOS and similar services are referred to as Fiber To The Premises (FTTP) or Fiber To The Home (FTTH) services.

FOC

Firm Order Commitment. A term used by Hosted VoIP providers to describe the date when your previous carrier should complete porting your phone number(s), making it (or them) available to use under your new carrier. For other telecommunications services, FOC can also refer to the installation date for T1 or DSL lines.

G711

Also called Pulse Code Modulation, G711 is a commonly used audio codec that compress and decompress audio signals for digital transmission. G711 requires more bandwidth than other codecs, but the payoff is better sound quality.

G729

A compression codec that compresses and decompresses voice data into units of 10 milliseconds. G729 has lower bandwidth requirements than G711, which can affect the quality of the voice data. DTMF or fax tones and music can’t be transported within the G729.

Gateway

A hardware device (e.g., a router, server, firewall, etc.) that serves as the junction that enables data traffic to flow between two networks, usually between a remote network and its host network.

Hosted

A technology service where your provider oversees the physical servers and other system infrastructure from a remote site.

Hosted VOIP

A VoIP phone service where the necessary hardware and software are maintained and updated off-site by your provider.

Hunt Group

See Ring Groups

Hybrid-Hosted

A phone system that combines your existing on-premises Private Branch Exchange (PBX) equipment with a cloud-based VoIP service.

IAD

Integrated Access Device. A device used at your location (CPE) that integrates multiple information signals from different phone sets (including analog and digital devices) into a common format.

ILEC

Incumbent Local Exchange Carrier. A telephone company that provided local service when the Telecommunications Act of 1996 was passed. The Act loosened regulatory barriers, allowing new telephone companies (CLECs) to enter the industry and compete with established telephone service providers.

Inbound Call Filters

A special phone-system option that routes calls based on their incoming number. VIP calls can bypass auto attendants and go straight to an assigned extension. Unwanted callers can be funneled to a custom message or automatic hangup.

Individual Call Logs

The collection of statistical and procedural data from your incoming and outgoing calls. This data is then organized and made available in reports. Call logs typically gather data like dates, times, call duration, users, extensions dialed, and final outcomes.

Intercom

A device that enables one- or two-way communication. IP phones will often come with an intercom function through the speakerphone. VoIP services often deliver the intercom feature on a one-to-one basis, or a one-to-many for widespread announcements.

International Calling

Calls made between different countries. Rates for international calls used to be extremely expensive, but have declined due to technological advances.

IP

Internet Protocol. A method or protocol used to send information online as digital packets from one device to another. Each computer or device connected to the Internet is assigned a unique IP address, which aids in the sending and receiving of information packets.

IP Address

A unique set of numbers that serves as address and identification for any device (computers, routers, printers, modems, etc.) connected to a network. This number allows the devices to communicate with each other via the network by embedding a source IP address and a destination IP address into every packet that crosses the network.

IP Phone

A phone that converts audio/voice to a digital signal/packets to send over the Internet. Instead of connecting to an analog phone line, it connects to the Internet via an Ethernet cable or wirelessly.

ISDN

Integrated Services Digital Network. Set standards for the transmission of digital voice, video, data, and other signals through the traditional copper wire telephone service used by the Public Switch Telephone Network (PSTN). ISDN is credited as an early high-speed Internet service that has since been replaced by DSL and modern cable service. In this kind of network, there are two service levels: Basic Rate Interface (BRI) and Primary Rate Interface (PRI).

ISP

Internet Service Provider. A company that provides you with Internet access, usually through a dial-up, DSL, or broadband connection. ISPs can also offer related services like email accounts, web hosting, domain name registration, and even data communications and telephone services (see VoIP).

ITSP

Internet Telephony Service Provider. A supplier of digital telecommunications services using Voice over Internet Protocol (VoIP). The Internet connection is established using IP phones or a Private Branch Exchange (PBX) system using Internet Protocols (IP) like SIP and H.323.

IVR

Interactive Voice Response. Automated technology that allows your callers to use keypad dial-tones (see DTMF) or their voices to select from a menu of options. This technology is usually helpful in directing these calls to most appropriate member of your team.

IXC

Interexchange Carriers. A telecommunications carrier, typically referred to as a “long-distance carrier.” They provide long-distance service between Local Exchange Carriers (LECs) across multiple Local Access and Transport Areas (LATAs). Examples of widely recognized IXCs include AT&T and Sprint.

Jitter

The variation in the time it takes for packets of information to travel across a network. Jitter is caused by any deviation or displacement in the packet’s path, causing a delay in the packet delivery, or causing the packets to arrive in a different order. For a caller, jitter is experienced as choppy, poor quality audio.

Kbps

Kilobits Per Second. The unit used to measure data transfer speed.

LAN

Local Area Network. A group of computers or devices connected to each other in a small area like an office, a building, or a campus. This shared high-speed network allows the sharing of resources and data, including telephone services, files, printers, scanners, and other applications. A LAN is different from a Wide Area Network (WAN), which isn’t bound by a geographic area and is made up of several connected LANs.

Last Number Redial

A feature that allows you to redial the last number your phone either called or received.

LATA

Local Access Transport Area. A US term for a geographic region where one or more telephone companies— or Local Exchange Companies (LECs)—provide telecommunications services.

Latency

The time it takes for a packet of information to be transmitted and received over the Internet, typically measured in milliseconds. In a VoIP system, a latency higher than 100 milliseconds (ms) causes your caller to experience audio that lags.

LDAP

Lightweight Directory Access Protocol. An open software protocol that allows you to access information directories, usually consisting of contact information, contained on a server.

LDAP Integration

A software feature that allows you to retrieve LDAP information through devices like an IP phone. This option simplifies configuration and management of central directories by pulling contact information from the directories you already use.

LEC

Local Exchange Company. A company that provides local telecommunications services within specific territories known as Local Access and Transport Areas (LATAs). Those companies that existed before the Telecommunications Act of 1996 are identified as Incumbent Local Exchange Carriers (ILECs). Companies formed to compete with ILECs after passage of the Telecommunications Act of 1996 are called Competitive Local Exchange Carriers (CLECs). These companies only handle local calls, leaving long-distance calls to Interexchange Carriers (IXCs).

Legacy

An unflattering term for a system, device, or technology (usually a computer or phone server) that you already have in place and have invested money in, but now it’s outdated, unsupported, no longer in production, and in need of replacing.

Line Failover

A backup operation feature you use to designate an alternate call path in case a call can’t reach you at your assigned DID. The call can automatically switch to ringing another internal extension, an external number (like a cell phone), or a voicemail box.

LNP

Local Number Porting. The ability of a Local Exchange Carrier (LEC), at your request, to reassign your existing phone number to another carrier, a new location, or to a different service.

LOA

Letter of Agency or Letter of Authorization. A document you complete and return to your new carrier that authorizes the new carrier to act on your behalf when it comes to communications matters. This is normally obtained so that your new carrier can request Local Number Portability (LNP) from your previous carrier, transferring your number from the losing carrier to the new carrier.

Local & Long-Distance Dial Tone

A sound used by telephone systems to indicate that the network or Private Branch Exchange (PBX) is working and that your phone is ready for you to dial.

Local Directory on Phone

A local or personal directory separate from the corporate directory and maintained on your personal device, usually as pre-programmed numbers on your speed dial.

MAC

Media Access Control A unique 12-digit, alphanumeric string that identifies a networking device, like an IP Phone.

MAN

Metropolitan Area Network. A high-speed data network that connects multiple Local Area Networks (LANs) spanning a metropolitan area, like a town or city. A MAN is larger than a LAN which takes in a building or a campus, but is smaller than a Wide Area Network (WAN) which typically takes in a wider geographic range.

Mbit

Megabit. A unit used to measure digital data. A Megabit is approximately 1 million bits, roughly ⅛ the size of a Megabyte (MB).

Mean Opinion Score (MOS)

A subjective benchmarking method used to measure the quality of human speech after it has undergone transmission and compression.

Message Waiting Indicator

A feature that notifies you of new or unheard voicemail messages. This feature is available as a lamp on your phone, a special tone, or as an icon on an online user portal.

Mobility

The ability to remain connected to your office telecommunications service even when you’re not in the office, including the ability to make and receive calls as if you were still at your desk. When VoIP providers discuss mobility, it is usually in reference to a combination of features that include voicemail to email, presence monitoring, instant messaging, video conferencing, unified communications, and softphones.

Modem

A device that enables your computer to send digital signals via the Internet using a telephone line. The modem converts (or modulates) the digital signal, which doesn’t transmit efficiently over a phone line, into an analog signal that does. Once the analog signal reaches its intended target, the receiving modem converts it back into a digital signal (demodulation).

MPLS

Multi-Protocol Label Switching. A protocol that simplifies and speeds up the transmission of data packets, directing them from one network node to the next. MPLS is the standard carrier mechanism for telecommunications networks.

NANP

North America Numbering Plan. An international telephone numbering plan integrating the telecommunications services among 20 countries, the majority of them located in North America. The plan establishes a basic numbering method for telecommunications within these countries.

NAT

Network Address Translation. A process that allows a network device like a firewall to assign one set of Inter Protocol (IP) addresses to computers within a private network, or local area network (LAN), and a second set of IP Addresses for external traffic. Inter-network traffic is remapped, converting an internal IP to one of the preassigned IP addresses specified for outgoing data. Companies use NAT to cut down on the number of IP addresses they need and to provide an extra layer of security.

Network Closet

A room in most offices where all of the computer networking hardware, voice circuits, and PBX equipment are located. This is commonly labeled an on-premises system.

On-Premises vs. Cloud

Refers to where the hardware controlling your VoIP service is housed and who is responsible for managing and maintaining it. With an on-premises solution, you are responsible for the hardware and the service costs. Hardware is literally housed on your premises, in your office. In a hosted environment, your service provider is responsible for all the operating costs and you simply pay for the service you use. The hardware that supports cloud services is usually housed in datacenters and delivered via the cloud.

Online User Portal

A private website companies use to provide you with an easy, intuitive, and personalized entry point where information, documents, tools, links, and other services can be accessed 24/7.

Packet

A basic unit of data used for communication over the Internet. It is transmitted between origin and destination through a process called Packet Switching.

Packet Loss

When one or more Packets are lost while in transit during the Packet Switching process. To the caller, packet loss comes across as audio that drops in and out, or calls that are dropped completely. Packet loss is measured by the percentage of packets lost from packets sent.

Packet Switching

A communications method that sends information through a digital network by breaking up that message into smaller pieces, called packets. Packets contain a specific destination address, which means they can be dynamically routed, taking different paths to arrive at the same destination where the packets are reassembled in their proper order.

Paging

A public address system that enables users to quickly reach another colleague in the communications network over a speakerphone. Sending pages is a method to send messages without having to wait for a ringtone, or for the person on the other end to pick up. It is particularly useful for brief, urgent messages or for broadcasting announcements to several colleagues at once.

Paperless Fax

See Fax to Email.

PBX

Private Branch Exchange. A private telephone network used by companies to connect their internal office lines to the Public Switched Telephone Network (PSTN).

Ping

The measurement of how long it takes for a packet of data to travel from your computer to the server and back.

PoE

Power over Ethernet. A technology that allows your network cables, like Ethernet cabling, to carry both data and electricity to a device. This alternate power connection lets you cut down on the number of cords you need and frees you from having to hunt for conveniently placed outlets when installing your phones around the office.

POP

Point of Presence. The demarcation or local access point between different networks. This is usually where the hand off occurs between your local network—provided by your Internet Service Provider (ISP)—and the rest of the Internet.

Porting Numbers

The ability to transfer your current number from your existing Local Exchange Carrier (LEC) to your new service provider. See LNP.

POTS

Plain Old Telephone System. The standard analog-signal telephone service employed by homes and businesses. Signals are transmitted along copper wiring, as opposed to non-POTS service that typically transmit along digital connections. See PSTN.

Presence Monitoring

A phone feature that allows you to visually monitor activity on other lines in your system. Generally, this is used to know whether an employee is on an active call. Activity is indicated by lamp fields on the phone that light up when a line is in use.

PRI

Primary Rate Interface. A dedicated and managed digital dial tone used on an Integrated Services Digital Network (ISDN) that transmits voice, video, and data traffic for large organizations.

Private IP Address

An Internet address created strictly for use on an internal network. Private addresses are issued by a network device, like a router, which draws them from a set of addresses assigned to it by a DHCP server. To access the Internet, a private address is converted to a public IP address via a network address translation (NAT) service.

Provisioning

A telecommunications process that involves configuring specific IP Phones for easy deployment so they securely connect with your VoIP phone system. This is normally performed by the provider before the phone arrives at your office.

PSTN

Public Switched Telephone Network. The traditional, circuit-switched telephone network. This system uses copper-wire telephone lines to convey analog or digital voice signals by setting up a path (a dedicated channel or circuit) that is created between two points for the duration of your call.

Public IP Address

The unique, Internet-facing IP address assigned to your device by your ISP. A public address means it can be reached through the Internet. On a shared network, attached devices may have their own private IP addresses, but when connect through an Internet connection, they are converted to the public IP address assigned to the router.

QoS (Quality of Service)

A protocol used to prioritize important outbound traffic to help your network achieve optimal bandwidth usage. In Voice over IP, this is a Router-based standard that protects your call quality when voice and data are run over the same network. Key measurements of QoS include jitter, latency, and packet loss, and of which impact your call quality.

Rate Center

A geographic area that determines the boundaries for local calling in the Public Switched Telephone Network (PSTN). Rate centers are used by Local Exchange Carriers and identified by an assigned area code.

Redundancy

A backup component that could be either hardware- or software-based. Redundancy is typically a feature included in virtual or cloud-based services used to provide continuous service in case another component fails, or to quickly and automatically restore service.

Report Caller Hold Time

A phone feature, often for Contact Centers, that informs you how long a caller has been on hold before you pick up the call. This gives you a head’s up on how frustrated your caller may be and help you to proactively defuse the tension as soon as you pick up the phone.

Ring Groups

A feature that automatically rings multiple phones when a specific DID or extension is dialed.

RJ11

The standard telecommunications cable connector or interface you plug into your phone to connect it to the telephone network. It’s usually designed as two clear plastic jacks connected by a cable. Each jack typically features four or six wire connections.

RJ45

A telecommunications interface you’re likely to use when setting up a data network. The RJ45 is similar to the RJ11, except its connectors typically feature eight pins, and it serves as the interface for data—or Ethernet—networks instead of telephone networks. The clear plastic jacks of the RJ45 usually have a Cat 5 cable running between it, creating a connection between a network device (like a router) and a network card.

RJ9

The telecommunications jack or cable connectors you use to connect your phone’s handset to the telephone base unit. It looks like a smaller version of an RJ11.

Router

A network device you use to connect your computer (or computers) to a data network. Using this connection, the router also intercepts, deciphers, and—based on the destination IP address—directs information packets that travel between networks.

RTP

Real-time Transport Protocol. A network protocol that manages the real-time transmission of voice and video data Packets over an IP network. Streaming, telephony, and web-based systems favor RTP and its rapid delivery over other transmission protocols, like Transmission Control Protocol (TCP), which give priority to data integrity over speed.

Server

A computer or device that stores and manages your network data and serves it to individual workstations connected to your Local Area Network (LAN) or Wide Area Network (WAN).

Service Uptime

A performance metric used to determine the amount of time a system or device is operational. The measurement is usually expressed in nines, such as: “The system is operational 99.99 percent of the time.”

SIP

Session Initiated Protocol. A standard communications protocol that establishes, modifies, and terminates real-time multimedia communications sessions transmitted over networks connected by IP Addresses. These communications generally include Voice over Internet Protocol (VoIP) calls, video conferencing, and online gaming. For VoIP calls, SIP uses other protocols, including Real-time Transport Protocol (RTP) and Secure Real-time Transport Protocol (SRTP).

SIP Trunk

A single transmission channel between your existing analog or premises-based Private Branch Exchange (PBX) and your Internet Telephony Service Provider (ITSP) that offers very limited Hosted Voice over Internet Protocol (VoIP) functionality without having to replace your entire phone system.

SIP Trunking

Using a virtual link or connection to replace your traditional telephone line (or trunk) to transmit voice, data, and video via the Internet rather than through the Public Switched Telephone Network (PSTN).

Softphone

A software app that mirrors the functionality of your Hosted VoIP service, allowing you to use your desktop computer, tablet, or smartphone device just like you would your desktop handset.

Speed Dial

A function that lets you enter regularly dialed numbers into a phone’s memory so you can place calls using fewer buttons.

Spy

A call-monitoring function that lets you enter an existing phone call and listen passively without interrupting the ongoing call or notifying either of the callers. Spy is one of three possible modes (see Barge and Whisper for the others).

Static IP Address

An IP address assigned by your Internet Service Provider (ISP) that doesn’t change. This is in contrast with a dynamic IP address, which is more common and are assigned whenever your device connects to the Internet.

STRP

Secure Real-time Transport Protocol. An extension of Real-time Transport Protocol (RTP) that features enhanced security measures. The protocol provides encryption, confidentiality, message authentication, and replay protection to your transmitted audio and video traffic. SRTP is usually intended for use in Voice over Internet Protocol (VoIP) communication.

Switch

A device or phone network component that connects your phone line with another line to establish a telephone call. Early telephone technology relied on human operators to provide manual switching services. Current Voice over Internet Protocol (VoIP) technology uses virtual or digital switches to connect phones to the Internet.

T-Carrier System

A set of digital data transmission formats predominantly used in North America and Japan. Both the T-Carrier and E-Carrier systems operate using Digital Signal 0 (DS0) as its basic unit, enabling a transmission rate of 64 Kbps.

T-38

A Codec commonly used to transmit real-time fax data over Voice over Internet Protocol (VoIP) networks. Faxes can’t travel over a data network the same way they do across an analog connection. The T.38 protocol helps convert the fax from an analog signal to an image, and then back to an analog signal when it arrives at its destination. Most VoIP Gateway devices and Analog Telephone Adaptors (ATAs) support the T.38 protocol.

T1

A high-speed digital data transmission line, the most commonly used line in the T-Carrier System. T1 lines originated as copper wire but now include fiber optic and wireless connections. A T1 carries 24 digital voice channels and can transfer your voice and data at a rate of 1.544 Mbps, 60 times faster than the standard telephone line.

TCP

Transmission Control Protocol. A data transmission protocol that enables your computer to talk to another computer. TCP is one of the core protocols governing Internet data exchange, dictating how a connection is created between networks, as well as ensuring information is converted into packets, sent, and arrives at its destination.

Toll-Free Number

A phone number your customers can use to call your business without racking up any charges. Any minutes or service costs are paid by you. Instead of an area code, toll-free numbers typically begin with one of these three-digit codes: 888, 877, 866, 855, 844, or 800.

UC&C

Unified Communications and Collaboration. A single interface that combines Unified Communications tools for real-time and non-real-time collaboration. This interface usually includes tools like chat, voice, email, presence monitoring, click to dial, and video and web conferencing. Unified Communications and Collaboration can refer to both cloud-based and premises-based systems.

UCaaS

Unified Communications as a Service. Unified Communications delivered through a cloud-based model. Companies using a UCaaS service rely on a third-party provider to deliver tools like voice, video, chat, fax, and email over an IP network.

UDP

User Datagram Protocol. A data transmission protocol used as an alternative to Transmission Control Protocol (TCP). Like TCP, UDP sends data Packets to an IP Address. Uses for UDP include Voice over IP (VoIP) and video conferencing.

Unified Communications

A suite of integrated business communications services. These services can be offered through an integrated platform or as several products with a similar user interface. Unified Communications include a wide range of real-time and non-real-time applications like voice, chat, text/SMS, presence monitoring, video and web conferencing, email, and fax. Unified Communications has become a marketing buzzword that is often used interchangeably with UC&C, UCaaS, and unified messaging. See the other definitions to note the differences between these terms.

Unified Messaging

A business solution that integrates electronic messaging technologies (like email, fax, chat, and voicemail) so that all communications are accessible via a single interface. Unified messaging is often used interchangeably with Unified Communications, though unified messaging is usually a feature offered in a broader Unified Communications service bundle.

UPS

Uninterruptable Power Supply, or Uninterrupted Power Source. A device that provides emergency battery power to computers, networks, and IT systems. In a Cloud VoIP system, UPS devices are used to provide emergency power to phones during an electrical outage.

Video Conference

Technology that allows real-time transmission of video and audio data between two or more locations across a network. Video conferencing is used to reduce the time and expense created by business travel. Its general purpose is to enable easy, face-to-face business negotiations, meetings, and job candidate interviews.

Voicemail

Any system or feature that records, stores, and plays back voice messages. Voicemail is usually a basic feature offered by telecommunications services. Voicemail messages are typically stored on your service provider’s server in a space designated as your voice “mailbox.”

Voicemail to Email

A feature that sends a notification to your email account that you’ve received a new voicemail. With many services, this notification can arrive with the message included as an audio attachment, a transcript of the message, or a link to where the message is available. Voicemail to email frees you from constantly having to check your voicemail box for new messages. They come to you and are easily accessible via phone, tablet, or computer.

VOIP

Voice over Internet Protocol. Technology that allows you to transmit voice calls as digital data packets through IP networks rather than use the traditional method that sends analog signals sent along the Public Switched Telephone Network (PSTN). Placing a VoIP call can be performed with a regular phone, special IP phones, or mobile devices.

VPN

Virtual Private Network. Network technology that uses a public network, like the Internet, to establish a secure connection between private networks. Voice, video, and data traffic can then be sent and received as if you were connected via a secure and encrypted Local Area Network (LAN), even though a VPN operates more like a Wide Area Network (WAN).

WAN

Wide Area Network. Several connected Local Area Networks (LANs) or Metropolitan Area Networks (MANs), spanning a large geographical area like a state or country. The networks that make up a WAN are often connected using public networks like telephone lines or data lines. The Internet is an example of a large, worldwide WAN.

Web Conference

An audio-based real-time communications service that allows you and other users to connect through their web browser. This service uses Transmission Control Protocols (TCP)/Internet Protocols (IP) connections and UDP/RTP protocols. Web conferencing typically facilitates large group meetings like webinars, webcasts, meetings, town hall meetings, and trainings. Features that often accompany a web conferencing service include screen sharing, texting, and video conferencing.

WebRTC

Web Real-Time Communication. An open-source project that supports real-time communications using a web browser or mobile application, without the need for a plug-in or additional software. These real-time communications include peer-to-peer voice, video, file-sharing, chat, and other data-sharing functions.

Whisper

A call-monitoring feature that allows you to listen to a call between a customer and an agent and speak to the agent without the customer being able to hear you. This feature is often used to help train new agents or provide them with live assistance without the caller being aware (see Barge and Spy).

WiFi

Wireless Fidelity (according to some sources, while others argue WiFi is simply a trademarked phrase). A wireless networking technology that uses radio waves to provide connectivity between computers and devices in certain areas called a hotspots or Wireless Local Area Networks (WLANs). WiFi emits frequencies between 2.4GHz and 5GHz, which are compatible with most computers and mobile devices.

WLAN

Wireless Local Area Networks. An area around a WiFi router that provides you with connectivity to a network and its resources, typically including Internet access.