Terms definitions
  • ACD
    ACD Stands for Average Call Duration.
  • ADSL
    ADSL means Asynchrone Digital Subscriber Line. Transmission mode of the data by the phone network allowing a fast and permanent connection.
  • ASR
    The answer/seizure ratio (ASR) is a measurement of network quality and call success rate in telecommunications. It is the percentage of answered telephone calls with respect to the total call volume.
  • Asterisk
    Asterisk is a PBX free software, multi-plateform, published under license GPL per Spencer Mark of the Digium company. Asterisk allows, voice mail, conference calls, vocal servers, and a good call management. Asterisk implements protocols H323 and SIP, as well as a specific protocol named IAX (Inter-Asterisk eXchange). This IAX protocol allows the communication between a customer and an Asterisk server as well as between two Asterisk servers.
  • ATA
    ATA or the analog telephone adaptor is the hardware device that connects the conventional telephone to the Internet through a high speed bandwidth line, provides the interface to convert the analog voice signals into IP packets, delivers dial tone and manages the call setup.
  • Backbone
    A general word used to describe the core of a network, ie the main trunk routes running between different points, from which all other smaller routes originate.
  • Bandwidth
    Bandwidth is the volume of data that can be transmitted over a communication line in a fixed amount of time. It is measured as a bit rate expressed in bits/s or multiples of it (kbit/s Mbit/s etc...).
  • Billing Increment
    After the initial Minimum Billing Increment, you will be charged in this increment for your calls. For instance, if the Minimum Billing Increment is 30 seconds and the Billing Increment is 6 seconds (30/6) and your call lasts 34 seconds you will be billed for 36 seconds (30 + 6 = 36). Common billing increments are 6 seconds, 30 seconds and 60 seconds.
  • BLF
    BLF as Busy Lamp Field is used as presence or state indicator. This option is generally used by phone equipment to allow a resource person to know at all time the status of other phones (not busy, ringing, busy, etc...)
  • BLI (Busy Lamp Indicator)
    A light or LED on a telephone that shows which line is in use.
  • Broadband
    It is a term used to define high speed Internet connection, generally provided by cable TV, DSL or dedicated telecom lines. The high speeds are achieved by the carrying capacity of the cable that can carry multiple messages simultaneously.
  • Centrex
    Centrex is a PBX-like service providing switching at the central office instead of at the customer's premises. Typically, the telephone company owns and manages all the communications equipment and software necessary to implement the Centrex service and then sells various services to the customer.
  • CLEC
    stands for Competitive Local Exchange Carrier. A CLEC typically builds and operates a communication network to provides its customers with an alternative to the local telephone company (ILEC).
  • CLI
    Caller Line Identity (CLI) is the piece of information that displays on your telephone the number of the person calling. Some telephone systems are unable to pass this information. However, the majority of customers are now demanding that CLI is available as a requirement.
  • Codec
    Algorithm allowing to compress and decompress audio and video files without losing a considerable quantity of information. Once a file was compressed by a codec such as MP3 or RealAudio, it is smaller and easier to transmit on the Web, but preserves a sound quality faithful to the original.
  • CSR
    A CSR is a copy of how your telephone records appear in the telephone company’s database. It contains information about each separate line charge (i.e. type of service, access charge, calling blocks on the line, 911 charge, etc.) that encompasses your monthly service charge on your bill. In addition, a CSR reveals the service location of the account, the billing address, additional directory listings, PIC designations, features that are being charged and on which line these features appear.
  • Debit
    Amount of information transferred within a specified amount of time OR transfer rate.
  • DID
    Direct Inward Dialing (DID) which is also called Direct Dial-In (DDI) in Europe, is a feature offered by telephone companies for use with their customer's PBX systems, whereby the telephone company (telco) allocates a range of numbers all connected to their customer's PBX. As calls are presented to the PBX, the number that the caller dialed is also given, so the PBX can route the call directly to the desired person or bureau within the organization. This feature enables companies to have fewer lines than extensions, while still having a unique number for each extension that is callable from outside the company. As an example, each extension of the PBX system may be assigned a seven digit external telephone number, with a fixed four or five digit prefix. Someone who knows the internal extension of his/her correspondent can dial the seven-digit number and be connected directly to the person called, bypassing the operator or PBX auto-attendant.
  • DISA
    Abbreviation for "Dial-In System Access" which indicates a Private branch exchange (PBX) feature in which a caller (upon entering a code through a touch-tone phone) gets another dial tone for accessing some or all of the features of the PBX, such as making an overseas call or leaving a voice mail message.
  • DNIS
    Short for Dialed Number Identification Service, a telephone service that identifies for the receiver what telephone number was dialed by the caller. A common use for this type of system is 800 and 900 phone numbers that often channel multiple phone numbers into the same PBX system. Once the call enters the PBX system, the DNIS will identify which number was dialed and record that information.
  • DTMF
    Dual-Tone Multi-Frequency is a signaling type which is used for signaling over the line in the voice frequency band to the switching centre. In modern terms, it is known as Touch Tone, a form of dialing by pressing a series of numbers.
  • E911
    Enhanced 9-1-1 or E9-1-1 service is a North American telecommunications based system that automatically associates a physical address with the calling party's telephone number, and routes the call to the most appropriate Public Safety Answering Point (PSAP) for that address. The caller’s address and information is displayed to the PSAP calltaker immediately upon call arrival. This provides emergency responders with the location of the emergency without the person calling for help having to provide it.
  • Echo canceller
    A device used to remove the echo found on a phone line as a result of delay. It can be the result of the length of the circuit being used for the call, or delay in the packets arriving at their destination in the case of VoIP. In effect, echo cancellers should be used on any long distance calls, or calls over IP or on mobile networks.
  • FOCD
    Stands for "Firm Order Confirmation Date". Generally used to specify which date a portability will complete.
  • Full duplex
    The full-duplex is very often the association of two channels simplex, as a highway is the association of two roads with only one direction. The connection full-duplex can be compared with a phone conversation where the two interlocutors can speak at the same time.
  • FXO
    FXO (Foreign Exchange Office) is a telephone interface that receives POTS. Analog telephone handsets, fax machines and (analogue) modems are FXO devices.
  • FXS
    FXS (Foreign Exchange Station) is a telephone interface which provides battery power, sends dial tone, and generates ringing voltage. A standard telephone plugs into such an interface to receive POTS.
  • G.711 (uLaw, aLaw)
    An ITU-T PCM half-duplex codec that uses either A-law or U-law compression (64 kbps, high quality, minimum processor load).
  • G.723.1
    An ITU-T double rate CELP codec (6.4/5.3 kbps, medium quality, high processor load).
  • G.726
    An ITU-T ADPCM wave form codec (16/24/32/40 kbps, good quality, low processor load).
  • G.729
    Is an audio data compression algorithm for voice that compresses voice audio in packets of 10 milliseconds duration. Music or DTMF tones can only be transported reliably with this codec using the RTP Payload for DTMF Digits, Telephony Tones, and Telephony Signals. (8 kbps, medium quality, high processor load)
  • Gateway
    A Gateway is an equipment, a computer which route telephone calls through several type of networks such as the traditional network of telephony (network STN) and Internet network. A Gateway is often connected to a platform of distant invoicing or on site. When the customer wishes to make calls, the Gateway will be connected to the platform which will terminate the calls.
  • H.323
    gathers a whole of voice communication protocols, image and data on IP networks. It is a protocol developed by the International union of telecommunications (UIT-T) which defines it as “Communication systems multi-media in package mode”. It is derived from the H.320 protocol used on Integrated services digital network (ISDN).
  • Half duplex
    Half-duplex can be compared with a communication with walkie-talkies, one speaks (the other cannot speak at the same time) and when he releases the button (signal of end of conversation) the other can then speak.
  • IAX
    IAX (Inter-Asterisk eXchange) is the protocol native to Asterisk PBX and supported by a number of other softswitches and PBXs. It is used to enable VoIP connections between servers as well as client-server communication. IAX now most commonly refers to IAX2, the second version of the IAX protocol. The original IAX protocol has been deprecated almost universally in favor of IAX2.
  • ILEC
    An ILEC is the traditional telephone company. ILEC stands for Incumbent Local Exchange Carrier. In the U.S., the Regional Bell Operation Companies (RBOCs) were formed after the divestiture of AT&T. The Independent Operating Companies (IOCs) located in single cities or rural areas are commonly referred to as ILECs.
  • IP PBX
    An IP PBX is a private branch exchange (telephone switching system within an enterprise) that switches calls between VoIP users on local lines while allowing all users to share a certain number of external phone lines. The typical IP PBX can also switch calls between a VoIP user and a traditional telephone user, or between two traditional telephone users in the same way that a conventional PBX does. The abbreviation may appear in various texts as IP-PBX, IP/PBX, or IPPBX.
  • ISP
    Internet Service Provider (ISP) determines any service provider proposing the access to Internet and some complementary services. ISP connects to its customers using a data transmission technology appropriate for delivering Internet Protocol datagrams, such as dial-up, DSL, cable modem or dedicated high-speed interconnects.
  • IVR
    Interactive Voice Response is a software application that accepts a combination of voice telephone input and touch-tone keypad selection and provides appropriate responses in the form of voice, fax, callback, e-mail and perhaps other media. IVR is usually part of a larger application that includes database access. Common IVR applications include: bank and stock account balances and transfers, surveys and polls, caller authorization centers, etc
  • Jitter
    It is a term used to indicate a momentary fluctuation in the transmission signal. This happens in computing when a data packet arrives either ahead or behind a standard clock cycle. In telecommunication, it may result from an abrupt variation in signal characteristics, such as the interval between successive pulses.
  • Kbps
    Kbps for Kilo bits per second. A flow of a thousand bits a second.
  • Lag
    Is the term used to indicate the extra time taken by a packet of data to travel from the source computer to the destination computer and back again. The lag may be caused by poor networking or by inefficient or excessive processing.
  • Latency
    Latency is the time that elapses between the initiation of a request for data and the start of the actual data transfer. This delay may be in nanoseconds but it is still used to judge the efficiency of networks.
  • LCR
    Least Cost Routing (LCR) is a system that allows to select among several telecom operators, proposing the best road, for each call, according to several criteria such as the cost for the called destination and quality. LCR system is used by the operators for the management of their voice traffic, but also by certain companies wishing to optimize their costs of telecommunications.
  • LOA
    A Letter of Authorization (LOA) is a document authorizing a telecommunications provider to act on a consumer's behalf. This is generally required when switching a telephone service provider while keeping the current telephone number or any other service which requires transfer of information from one provider to another.
  • Mbps
    for Mega bits per second. A flow of a million bits a second.
  • MWI
    A message-waiting indicator (MWI) in telephony, is a term for a calling feature that illuminates an LED on select telephones to notify a telephone user of waiting voicemail messages.
  • OC3
    OC-3 is a network line with transmission data rate of up to 155.52 Mbit/s commonly used for data and voice carriers.
  • Origination
    Call Origination, also known as voice origination, refers to the collecting of the calls initiated by a calling party on a telephone exchange of PSTN, and handing off the calls to a VoIP endpoint or to another exchange or telephone company for completion to a called party. In the VoIP world , the opposite of call origination is call termination, where a call initiated as a VoIP call is terminated to the PSTN. The term is often used in referring to a VoIP trunking service.
  • Packet
    In network, a packet is a data transmission unit used to communicate. In order to transmit a message of a machine to another on a network, this one is cut out in several separately transmitted packages. A package includes the data, encapsulated in a header, including/understanding useful information to transport and decode the message.
  • POP
    A point-of-presence (POP) is an artificial demarcation point or interface point between communications entities.
  • Portability
    Fact of changing mobile operator while preserving your phone number.
  • POTS
    This abbreviation for "Plain Old Telephone Service" refers to the standard analog telephone service without extra enhancements. It remains the basic form of residential and small business service connection to the telephone network in most parts of the world but is now opposed to more advanced forms of telephony such as ISDN, mobile phones and VoIP.
  • PSAP
    A Public Safety Answering Point (PSAP), sometimes called "Public Safety Access Point", is a call center responsible for answering calls to an emergency telephone number for police, firefighting, and ambulance services. Trained telephone operators are also usually responsible for dispatching these emergency services.
  • PSTN
    PSTN, which stands for Public Switched Telephone Network, refers to the telephone system that transmits analog voice data. Till recently, PSTN was the heart of all phone systems worldwide. However, most of the developed world is now switching to or has switched to telephone networks that are based on digital technologies, such as ISDN and FDDI.
  • QoS (Quality of Service)
    A measure of parameters that affect the level of performance a network offers a specific type of traffic. QoS parameters include access priority, bandwidth availability, latency, jitter, and packet loss. Toll quality, real-time compressed and uncompressed voice and video require fairly immediate network access, guaranteed availability of bandwidth throughout the call, low latency, zero jitter, and zero loss. E-mail is at the opposite end of the QoS spectrum, as it is highly tolerant of a low level of priority; high levels of latency, jitter, and loss; and does not require any bandwidth availability guarantees during the course of a mail transfer. QoS also must ensure that granting a QoS level to one traffic type or call does not violate the data flow requirements of another traffic type or call. The circuit-switched public switched telephone network (PSTN) offers all applications the highest level of QoS. Asynchronous transfer mode (ATM) offers multiple QoS levels appropriate for different traffic types. Frame relay, Internet Protocol (IP), and Ethernet networks can employ various priority mechanisms to offer differential grade of service (GoS) levels, but cannot guarantee QoS.
  • RJ-11
    A connector RJ-11, also called Registered Jack 11 is an international standard used by fixed telephones. It however is also used in the field of the local networks. “RJ” for Registered Jack is part of the Code of Federal Regulations in the United States.
  • RJ-45
    A connector RJ-45 is a physical interface often used to finish twisted pair type cables and has eight pins of electric connections. “RJ” for Registered Jack is part of the Code of Federal Regulations in the United States.
  • Router
    A router is an intermediate element in a computer network. He has two principal functions; to define a table of routing and to switch packets of an interface towards another.
  • RTP
    RTP (Real-Time Transport Protocol) is commonly used with IP networks. RTP is designed to provide end-to-end network transport functions for applications transmitting real-time data, such as audio, video, or simulation data, over multicast or unicast network services. RTP provides such services as payload type identification, sequence numbering, time stamping, and delivery monitoring to real-time applications.
  • SIP
    SIP, which is the acronym of Session Initiation Protocol, is an IP telephony signaling protocol. It is primarily used for voice over IP (VoIP) calls, though with some extensions it can also be used for instant messaging. It is less complex than H.323, the other IP telephony protocol. [edit] SIP (Session Initiation Protocol)
  • SIP Client
    An RTC (real-time communications) client that uses SIP (Session Initiation Protocol) to establish and maintain RTC sessions with a SIP server.
  • SIP Server
    A server that uses SIP (Session Initiation Protocol) to manage real-time communication among SIP clients.
  • Softphone
    This is a software application that is installed in the user’s PC. It uses the Voice over IP technology to route voice calls over the net and provides several value added features, such as call forwarding, conference calling, and integration with applications such as Outlook for automatic dialing. The audio is provided through a microphone and speakers plugged into the sound card. The only limitation of a Softphone is that the phone call has to be made through a PC. Many softphone are free VOIP software downloads.
  • T.38
    T.38 is an International Telecommunication Union (ITU) recommendation for allowing transmission of fax over IP networks in real time.
  • Termination
    Call Termination, also known as voice termination, refers to the handing off or routing of telephone calls from one telephone company, also known as a carrier or provider, to another. The terminating point is the called party or end point. The originating point is the calling party who initiates the call. This term often applies to calls while using VoIP: a call initiated as a VoIP call is terminated using the PSTN. In such cases, termination services may be sold as a separate commodity. The opposite of call termination is call origination, in which a call initiated from the PSTN is terminated using VoIP. Thus, in "origination" a call originates from PSTN and goes to VoIP, while in "Termination" a call originates in VoIP and terminates to PSTN.
  • Trunk
    A communications channel between two points, typically referring to large-bandwidth telephone channels between switching centers that handle many simultaneous voice and data signals.
  • Uniform Resource Identifier - URI
    Uniform Resource Identifier (URI) is a string of characters used to identify or name a resource on the Internet. Such identification enables interaction with representations of the resource over a network (typically the World Wide Web) using specific protocols. Schemes specifying a concrete syntax and associated protocols define each URI.
  • Virtual fax
    A virtual Fax is an Internet based fax service enabling you to send and/or receive faxes by email. The faxes sent to you will be converted into a digital format sent directly to your email. This allows communication by fax without needing a fax machine.
  • Virtual Number
    A telephone number outside of the physical area code you reside in. Provided by telephone carriers and VoIP providers, it allows callers to make local calls from that area code to your phone. For example, if you live in Atlanta and have a virtual phone number with a San Francisco area code, anyone calling from San Francisco is making a local call.
  • VoIP Trunking
    Service providers can use this application to connect enterprise and call center customers directly to their VoIP network. By bypassing local operators and toll charges, the VoIP Trunking application enables service providers to offer attractive termination rates for both domestic and international long distance calling. This application connects seamlessly to the enterprise/call center's PBX, allowing employees to make off-net calls at reduced rates.
  • WiFi phone
    A WiFi phone is one that enables users to make phone calls from public WiFi hotspots or residential WiFI network environments. Besides voice calls, these phones can be used to send e-mails wirelessly.