VoIP Acronyms Guide

Acronym Stands for Meaning
ADSL Asymmetric digital subscriber line Enables faster data transmission over copper telephone lines than a conventional voice band modem can.
AP Access Point A device which forms a wireless network by connecting wireless communication devices together.
ATA Analog Telephone Adapter A device that coverts analogue voice signals to digital signals which can be transmitted over the Internet.

bd Baud The unit for symbols or pulses per second. It is the number of distinct signaling events made to the transmission medium per second in a digitally modulated signal or a line code.

BYOD Bring Your Own Device A term used to signify VoIP providers which allow a person to supply their own equipment or ATA.
CDR Call Detail Record A record about a specific call that includes details such as duration, origin, destination, cost information, and anything else. Also known as Call Data Record.
Codec Coder-Decoder A programme which converts analogue signals to digital signals or vice versa. It can be used in conjunction with compression software to compress and decompress these signals to varying degrees. A codec encodes a data stream or signal for transmission, storage or encryption, or decodes it for playback or editing. The term is also used as a generic name for a videoconferencing unit.
CPE Customer Premises Equipment Equipment at a customers location which is connected with a carrier’s telecommunication channel and converts the digital signal back to voice. Can include devices such as routers, set-top boxes, telephones, switches, residential gateways (RG), fixed mobile convergence products, home networking adaptors and internet access gateways that enable customers to access Communication Service Providers’ services and distribute them around their house through a LAN.
CSR Customer Service Record A document sent to a client of a telephone company, showing how their telephone records appear in the company’s database. Information shown includes services, billing activity, associated address and service orders tied to a certain phone number.
CSU Channel Service Unit A line bridging device that is used with a T-Carrier to perform loopback testing, provide a barrier for electrical interference from either side of the unit, and is the last signal regeneration point coming from the central office, before the regenerated signal reaches a multiplexer or DTE. It may also perform bit stuffing or provide a framing and formatting pattern compatible with the network.
DHCP Dynamic Host Control Protocol A communications protocol that allows network administrators to supervise and distribute IP addresses from a central point to each computer or device on a network.
DID Direct Inward Dialing A service which allows a company or organisation to allocate individual phone numbers to each user within its PBX system.
DNS Domain Name System A system for resources connected to the internet, which translates domain names to numerical IP addresses.
DS0 Digital Signal 0 A basic digital signaling rate of 64 kbit per second, corresponding to the capacity of one voice-frequency-equivalent channel.
DSL Digital Subscriber Line Provides internet access by transmitting digital data over a standard telephone network.
DSU Data Service Unit A telecommunications circuit terminating device that transforms digital data between telephone company lines and local equipment.
DTE Data Terminal Equipment A piece of equipment (usually a telephone) that is connected to the wires at the end of a telecommunications link and converts user information into signals or reconverts received signals.
DTMF Dual Tone Multi-frequency The signal that is generated and sent to a telephone company when a user presses a telephone’s buttons. These signals are two tones of a specific frequency designed so that a voice cannot duplicate them. The ability for interactive telephone menus to work across different networks and phone systems is due to the fact that DTMF tones are standardised and uniquely linked to a number, hash key or star key on the telephone keypad. Also known as Touchtone.
DTR Data Transfer Rate The speed whcih which a given amount of data travels from one place to another.
ECM Error Correction Mode Used in conjunction with memory storing fax machines, ECM allows for a receiving fax machine to ask for retransmission of a page where errors were detected in the frames. If the receiving fax machine is unable to receive an error free page the fax transmission may fail and the fax connection may be terminated. ECM has a low tolerance for packet loss, so fax transmissions will often fail on networks with packet loss when it is enabled.
ENUM Telephone Number Mapping Using Domain Name System (DNS) based architecture to map telephone numbers to domain names, in order to help facilitate VoIP.
FXO Foreign Exchange Office The plug on a fax machine, analogue phone system or analogue modem. Since the FXO port is attached to a device, the device is often called an ‘FXO device’.
FXS Foreign Exchange Station The port or plug that delivers an analogue phone line. It provides a dial tone, battery current and ring voltage.
GR-909 Test GR-909 Test A suite of electrical tests which some VoIP routers include in their diagnostic tools. They test for problems like unwanted voltage on phone lines, off hook devices keeping the line open, or no phone being connected to the line.
IAD Integrated Access Device Equipment at a customers location that provides access to wide area networks and the Internet, and is used to convert digital signals back to voice.
IAX Inter-Asterisk eXchange Protocol (Pronounced “eeks”) is an Asterisk communications protocol for setting up interactive user sessions (both audio and/or video) and supports any type of codec. Now commonly means IAX2.
IM Instant Messaging Real-time communication between two or more people, using ‘presence’ which enables users to see other user’s availability status.
IPBX Intranet Private Branch Exchange A telephony solution for a business or organisation where the primary means of exchanging voice internally is VoIP.
ISDN Integrated Services Digital Network A telephone system for digital transmission of voice and data over ordinary telephone copper wires.
ISDN BRI ISDN Basic Rate Interface Basic ISDN speed up to 128 Kbps.
ISDN PRI ISDN Primary Rate Interface Primary ISDN speed up to 2 Mbps.
ITSP Internet Telephony Service Provider A provider that uses your Internet connection to deliver telephone service, such as Vonage.
IVR Interactive Voice Response An integrated software information system that speaks to callers. Callers use touchtone keypad entries to interact with the software, navigate menus and receive voice responses.
LAN Local Area Network A computer network that is restricted to a local area, such as a home, office, or group of buildings.
LERG Local Exchange Routing Guide A database of the first 6 digits of a telephone number that provides information for routing telephone calls over the Public Switching Telephone Network and enables identification of what company the number belongs to.
LNP Local Number Portability The ability of a telephone customer to keep their phone number if they switch to another local telephone provider. Taking your number to another phone company is known as ‘porting’.
MOS Mean Opinion Score A numerical indication of the perceived quality of voice transmission. 1 represents the lowest perceived audio quality and 5 is the highest.
MTA Multimedia Terminal Adapter A device that connects a traditional telephone to a cable, converting voice to digital signals.
NAT Network Address Translation An Internet standard allowing a local network to use a public IP address to connect to the Internet and a set of local IP addresses to identify individual devices in the network. NAT translations are a challenge for VoIP and can result in one-way audio in some cases.
NVP Network Voice Protocol A computer network protocol for transporting human speech over packetised communications networks.
PBX Private Branch Exchange A private telephone exchange system that performs concentration of central office lines and enables intercommunication between all telephones within the organisation. It also allows outside phone lines from a telecommunications provider to connect to extensions within the office. PBXs usually have several features such as call forwarding, rollover, paging and voice mail.
PI Presence Information A status indicator, common in IM and VoIP servers, which shows a users ability and willingness to communicate.
PoE Power over Ethernet A technology used to transmit both data and electricity over standard data network cables, to devices such as wireless access points or IP cameras.
POTS Plain Old Telephony Services A traditional standard telephone service on a single line system, provided by telecommunications operators.
PRI Primary Rate Interface A telecommunications interface standard used to provide telecommunication services to offices. It is used on an ISDN to carry multiple DS0 voice and data transmissions between the network and a user.
PSTN Public Switched Telephone Network The worldwide circuit-switched telephone networks that are operated by telephony operators who provide infrastructure and services for public telecommunication. It is made up of telephone lines, fiber optic cables, microwave transmission links, cellular networks, communications satellites, and undersea telephone cables, all interconnected by switching centers. Originally a network of fixed-line analogue telephone systems, it is now almost entirely digital and includes mobile and other networks, as well as fixed telephones.
RG Residential Gateway Allows the connection of a local area network to a wide area network.
RJ-11 Registered Jack-11 The standard 4 or 6 wire connector used to connect telephone equipment.
RJ-45 Registered Jack-45 An 8 wire connector used to connect Ethernets to computers, routers and other Internet devices. This connector is slightly larger than an RJ-11 telephone connector.
RTP Real Time Transport Protocol A standardised packet format for delivering audio and video over IP networks in real time.
SIP Session Initiation Protocol A protocol for creating, modifying, and terminating sessions such as internet telephone calls, multimedia distribution and multimedia conferences.
SIP Trunking Session Initiation Protocol Trunking A way to establish voice sessions between SIP Enabled PBXes and/or SIP clients over an IP Network.
STUN Simple transversal of UDP through NATs A protocol for assisting devices behind a NAT firewall or router with packet routing.
T-1 T-1 A hardware specification for telecommunications trunking. A trunk is a single transmission channel between a switching center and a node (such as a telephone).
T83 T83 A recognised standard for sending fax transmissions as UDP or TCP/IP packets over an IP network.
TCP/IP Transmission Control Protocol / Internet Protocol The technical protocol that defines the form of net data packets and how they travel to their destinations.
UDP User Datagram Protocol A communications protocol that does not provide sequencing of packets. The application must be able to put the message in the right order.
VAD Voice activation detection A software application that allows detects silence to use techniques to conserve bandwidth. Voice activation detection can also be used to forward idle noise or comfort noise to a remote IP telephone or IAD giving the illusion of a constant transmission stream during silence, so the listener would not think the line had gone dead. Also known as silence suppression.
VoIP Voice overInternetProtocol Also called IP telephony. The transmission of voice over the Internet (or any IP-based network), as digital packets rather than the traditional circuit-committed protocols of the PSTN. Also called IP telephony.
VoWLAN Voice over Wireless LAN Holding a voice conversation using WLAN. In other words, like VoIP over a Wi-Fi network.
WiFi Wireless Fidelity The trademark name of the WLAN products that are based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards. The term has come to be used in general English as a synonym for WLAN.
WiFi Dual Mode Phone WiFi Dual Mode Phone A phone which can easily switch between using a WiFi connection when one is available and a traditional cellular network connection.
WiFi Phone WiFi Phone A wireless telephone that looks like a mobile phone but places calls via VoIP and wireless internet rather than using a cellular network.
WLAN Wireless Local Area Network Communication between two or more computers, within a limited area, using radio communication to accomplish the same functionality that a wired LAN has.
XMPP Extensible Messaging and Presence Protocol An open-source, XML-based protocol for near-real-time instant messaging, presence information and contact list maintenance.