This glossary contains definitions for common telephony and related IT terms. Simply click on a letter below to find the definition of a word beginning with that letter.
Some telecommunication terms are used interchangeably within the industry, or are closely related. Rather than repeat definitions throughout this glossary, we have included links to related terms within the definitions for particular terms, where relevant.
It is hoped this resource will help you to select a telephone systems perfectly suited to the needs of your business, but should you require expert help, please do not hesitate to contact the friendly and experienced Best4Systems team.
A headset with one earpiece. See Monaural for definition.
A2DP is a Bluetooth profile and is short for "Advanced Audio Distribution Profile". This profile defines how audio multimedia can be streamed from one device to another over a Bluetooth connection. A2DP is also known as "Bluetooth Audio Streaming".
ACD is an acronym for ‘Automatic Call Distribution’. Please refer to ‘Call Hunt’ for more information.
This stands for an ‘Advanced Connectivity Interface’. This term simply refers to all modern telecommunications systems.
Acoustic Clarity is Polycom's patented Duplex technology, which enables a more natural conversation.
Acoustic Shock Protection
Acoustic Shock Protection (ASP) is the prevention of harm to hearing caused by acoustic shock, which is simply sudden & unexpected loud noises experienced via the telephone. Devices with this feature limit noise to 85dB. ASP is a voice circuit breaker that uses Digital Signal Processing (DSP) to protect users from these sounds.
ADA is shorthand for the ‘Americans with Disabilities Act’. ADA-approved phones ensure accessibility for disabled individuals, through the inclusion of large buttons, visual and amplified ringers, and/or Braille.
ADF is shorthand for the ‘Automatic Document Feeder’. This is commonly found in fax machines and printers and is used to feed the machine with documents for printing.
ADSL stands for “Asymmertic Digital Subscriber Line”. ADSL is a data communications technology that allows for fast data transfer over telephone lines. In ADSL, bit rate and bandwidth are said to be Asymmetric, which means it is more focused towards the customer premises (downstream) rather than the reverse (upstream).
An amplifier is a device that ampifies sound. In essence, it makes things louder. Amplifiers are commonly used with telephones as they are able to boost the sound emanating from the telephone to the headset. Modern headset amplifiers are also digital which enables them to do other fancy things such as providing Acoustic Shock Protection.
Analogue System Supported Featurephone
AnalogueAnalogue telephones and conference phones are simple 2 wire devices that can be used on a standard BT home line. Many analogue devices are compatible with digital and IP systems but will require the correct extension. You will need to contact network / IT team to find out which extensions you require.
ANR stands for "Active Noise Reduction". An ANR headset has a microphone inside the ear cup that picks up ambient noises. Sound is passed through electronics which produce a mirror image of the ambient sound at a non damaging decibel.
This stands for ‘Application Programming Interface’, a software-based interface which allows one program to interact with another.
This stands for ‘Analogue Private Network Signalling System’. An APNSS is the analogue version of DPNSS, a private networking standard.
"ARMS" is short for 'Automatic Remote Monitoring Service'. ARMS enables full automated monitoring to allow generation of reports. Faults such as a damaged handset or telephone knocked over will trigger a call to the management computer.
ASP is short foo 'Acoustic Shock Protection'. Please see Acoustic Shock Protection for more information.
ATC is an acronym for ‘Audio Tele-Conference’. Please refer to ‘Conferencing’ for more information.
Attenuation is the noise level that is removed from your environment, allowing you to work safely in high noise areas. More scientifically, it's the process of losing noise energy. There are three levels of protection:
Allows you to work in areas of exposure to noise levels between 87db(A) and 98db(A).
Allows you to work in areas of exposure to noise levels between 94db(A) and 105db(A).
Allows you to work in areas of exposure to noise levels between 95db(A) and 110db(A).
ATEX approved equipment has been specially designed and tested to work in explosive and dangerous atmospheres.
Auto dial is the name given to electronic hardware and software that dials numbers automatically. Once calls are answered, either a recorded message will play (this is sometimes known as ‘robocalling’ or ‘voice broadcasting’), or a human operator will interact with the called party.
Also referred to as an ‘AA’ or ‘virtual receptionist’, auto-attendant automatically transfers callers to certain extensions without the need for human intervention. The majority of AAs provide a simply menu of options for callers to choose from – pushing ‘1’ may take a caller through to a billing department, for example, while ‘2’ may transfer them to customer services.
Automatic Call Back
This computer-telephony feature gives those who ring a call centre (or other business premises) during a busy period the option to be called back later. Instead of a caller spending a frustrating length of time in a call queue, automatic call back will store the incoming number and dial it as soon as an operator becomes free.
Beam Forming Microphone Array
Bluetooth is a wireless technology standard usually associated with mobile phones. Bluetooth benefits from high levels of security, but is only effective over short distances.
This is the hour of the day that a telecommunication system handles the most calls.
Busy Hour Call Completion
BRI stands for “Basic Rate Interface”. A BRI is an ISDN (Integrated Services Digital Network) configuration.
This feature allows calls made from one number to be easily forwarded to another. This feature is useful for putting callers through to appropriate individuals and/or departments.
This telephone feature allows operators to pause a call, while they seek additional information for the caller, or activate another feature (Call Pickup, for example).
Call hunting is a method of distributing phone calls from a single telephone number to different extensions sharing the same line. Supported by many PBX systems and available from a number of service providers, call hunting uses an algorithm to direct calls to free lines efficiently. Call hunt is also known as Automatic Call Distribution (ACD).
This telephone feature allows an operator to place a call on hold from one terminal, and send it to an unused extension number so the call can be answered from elsewhere. For example, a department of a supermarket might be called from head office and told they have “a call waiting on 452” – the department would then dial 452 to attend to the call.
This feature allows employees to answer ringing phones they hear located at unattended terminals, simply by lifting their own respective handset. Caller ID Also known as calling line identification (CLID), calling number identification (CNID), calling line identification presentation (CLIP) and calling number delivery (CND), caller ID functionality is present on a variety of analogue and digital phone systems. It allows a name (if available) associated with a number to be transmitted to the called party during ringing (and vice versa), which is then displayed on a telephone’s built-in screen, or another device.
CAS – or ‘Channel Associated Signalling’ – is a type of digital signalling which uses routing information to send audio and other data to its destination.
This stands for ‘Computer Assisted Telephony’, which simply refers to telephone systems which make use of computer technology. CAT is also referred to as ‘CTI’ and ‘CIT’.
CAT-Iq is an acronym of 'Cordless Advanced Technology – internet and quality'. CAT-Iq was designed to be fully backward compatible with DECT and allows IP voice to operate within the DECT framework, which enables high quality Widebad VoIP.
CIL means ‘Call Information Logging’, a feature which automatically records information about calls made from, and received by, a terminal or extension.
CIT stands for ‘Computer Integrated Telephony’, another way of referring to ‘CAT’ (Computer Assisted Telephony).
Class of Service
Class of service is a traffic management method which groups similar data types (email, audio etc.) together as ‘classes’, each of which can be given its own service priority level, to ensure business deals with queries of the highest priority first.
This stands for ‘Calling Line Identification’. See ‘Caller ID’ for more information.
CND is an acronym for ‘Calling Number Delivery’. Please refer to ‘Caller ID’ for more information.
Computer Telephone Integration
Please see ‘CTI’ for more information.
A Connection Cord is the lead that connects your wired headset to your telephone. They are specific to the manufacturer of your headset, and there are a large number of variations to deal with the numerous choice of telephones available. You can use one of our handy connectivity guides to help you find the right connection cord.
Simply select your headset manufacturer from the list below.
Avalle compatibility guide
Plantronics compatibility guide
Jabra compatibility guide
Sennheiser compatibility guide
DDI (Direct Dial Inwards) allows operators to call extensions directly, without routing through a switchboard first. Using DDI, a business is able to offer personalised telephone numbers for specific members of its staff, without the need for physical PBX lines for each connection.
Dynamic Host Configuration Protocol Or “DHCP” is a Standardized protocol used on IP networks for dynamically distributing network configuration parameters, such as IP addresses for interfaces and services.
Digital Enhanced Cordless Telecommunications
Digital Enhanced Cordless Telecommunications is a digital communication standard which allows cordless telecommunication equipment to gain access to a fixed telecommunication network. At it's most basic level, it allows your cordless telephone or headset to use your telephone line.
Digital Signal Processing
Digital Signal Processing is a process where sounds, such as voice and audio, are digitalised in order that that they can be manipulated before being outputted.
DSS (Direct Station Select)
DN means ‘Direct Number’. This is a specific number assigned to any particular calling point (a department or individual, for example), negating caller interaction with a switchboard.
DND is shorthand for ‘Do Not Disturb’. When switched on, this phone setting will mute or redirect calls to a different, selected terminal.
The DPNSS – or ‘Digital Private Network Signalling System’ – protocol is a private networking standard which provides access to all of a telephone system’s features across multiple PBXs in a single private network.
DSP is an acronym of 'Digital Signal Processing'. Please see Digital Signal Processing for for information.
DTMF– or ‘Dual Tone Multi-frequency’ – refers to signals which are sent to other telecommunication devices (such as a switchboard) when buttons on a telephone are pushed. In the UK, the most common DTMF is ‘Touch-Tone’.
Duplex refers the ability for two connected parties to be able to talk simultaneously. Both parties can transmit at the same time. In a conference call for example, both parties can talk at the same time without it affecting the quality of a call. When this is not possible, this is referred to as simplex.
DXDP (Digital eXtra Device Port)
Dynamic Noise Reduction
An Ear Cushion is the soft cushion that sits between the headset earpad and your ear. These are usually either made of soft foam or soft leather. They come in many shapes such as circular and triangular, as well a doughnut shaped.
Electronic Hook Switch
Electronic Hook Switch is a cable used to connect a telephone to the base unit of a cordless telephone. This cable allows users to remotely answer the telephone if they are away from their desks. It replaces the slightly cruder handset lifter.
GAP is short for "Generic Access Profile". GAP compatibility allows handsets the be registered with GAP compatible base stations and will allow you to make and receive calls. Other telephony functions may be limited and mixing manufactures is not recommended.
HAC means ‘Hearing Aid Compatible’. HAC handsets (and other HAC technologies) do not interfere with hearing aids worn by anyone in close proximity – non-HAC models will often cause humming or whining noises in the ears of hearing aid wearers.
A handset lifter is a device that sits on your telephone directly below the handset. This device connects to the base unit of a cordless telephone and when activated by the headset, it will lift the handset of the telephone so that your call is answered and transferred to the headset.
HD Voice is the trademark name for Plantronics Wideband audio. Please see Wideband.
A headset port is a dedicated socket on your telephone to which you can connect a telephone headset. Please use our helpful buyers guide to telephone headsets.
HFA or HiPath Feature Access operating mode combines the advantages of an IP based work station with the comprehensive feature set of an HiPath communications platform. HFA workpoints are connected to the LAN which is connected to a PBX by a gateway. By changing the phone software, a switch from HFA to SIP is possible.
To learn about hybrid business telephone systems, please visit our System Buyers Guide.
Icon Buttons (Global)
Icon Buttons are soft and hard keys on your phone that have had the TEXT replaced with images. So instead of saying "Headset" there is an image of a headset. This is becoming more common as manufacturers, keen to sell in different countries, homogenise the manufacture of their products for these different markets, and reduce costs.
IP, which stands for 'Internet Protocol', manages the transfer of packets of data between IP address and is usually associated with TCP.
iPAQ refers to a Pocket PC and personal digital assistant as first termed by Compaq.
To learn about IPBX business telephone systems, please visit our System Buyers Guide.
Internet Protocol Security (IPsec) is a protocol designed to enable secure IP communications by encrypting each IP packet of a communication session.
Ingress Protection (IP Rating)
Products that have an IP rating will be able to operate in hazardous environments and will be protected against, depending on the IP rating, the intrusion of solid objects such as hands, fingers, accidental contact, dust and water in enclosed electrical enclosures.
Here are a few examples:
IP65 Protected from low pressure water jets in any direction
IP66 Protected from high pressure water jets in any direction
IP67 Protected against immersion up to 1metre in depth
IP68 Protected against long term immersion up to a specific pressure
ISDN stands for “Integrated Services for Digital Network”. This is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the traditional circuits of the public switched telephone network.
To learn about key systems, please visit our System’s Guide.
KSU is shorthand for ‘key system unit’ (also simply known a ‘key system’), a form of telephone system which is not connected to a PBX. To learn more about key systems, please visit our System Buyers Guide.
A telephone ‘line’ refers to a wire that carries telephone and telegraph signals.
"MEMS" stands for Micro Electro Mechanical System. MEMS is a technology of microscopic devices, particularly those with moving parts. MEMS are made up of components between 1 and 100 micrometers in size.
MIDI or "Musical Instrument Digital Interface" is a file format without audio signal or media. Instead it holds information about musical note like pitch , intensity, volume and vibrato.
Microsoft Lync is an instant messaging client used with Microsoft Lync Servers. There are many USB headset on the market that are Microsoft Lync optimised, and will benefit from additional features if used on a Microsoft Lync optimised servers and software.
Microsoft Office Communicator
Microsoft Office Communicator is the former name for 'Microsoft Lync'. See Microsoft Lync for more information.
MOC is an acronym of 'Microsoft Office Communicator' which is now known as 'Microsoft Lync'.
A modem port allows quick and convenient connection when sharing your telephone line with a computer.
This stands for Music on Hold.
Music on Hold
Neckband refers to the position headset is worn when in use. The neckband wearing style is worn around the neck.
NFC stands for "Near Field Communication". NFC is a set of standards for smartphones and similar devices to establish radio communication with each other. These connections are established by simply touching them together or bringing them into proximity, usually no more than a few inches.
Noise Cancelling refers to the microphone used on a device, usually a headset. These Noise Cancelling microphones cut out the background noise in your location, which helps you be heard more easily when having a conversation over the phone.
Omni Directional Microphone
Omni-Directional Microphones can pick up sound virtually from any direction. This design can be useful when a device needs to pick ambient sound or is used in an environment where the speaker is moving. This is in contrast to a Uni-Directional microphone which can only pick up sound from a specific side or direction of the microphone.
This feature allows frequently called numbers to be dialled with the simple push of one, pre-assigned button.
To learn about PBX business telephone systems, please visit our System Buyers Guide.
Plain Old Telephone Service
PoE & PoE+
PoE or 'Power over Ethernet' refers to electrical devices being able to receive electrical power from an ethernet cable at the same time as receiving data. Can be useful in reducing the amount of cabling required around the office.
PoE provides 15.4W of power per device (IEEE 802.3at-2003 Standard)
PoE+ provides 25.5W of power per device (IEEE 802.3at-2009 Standard)
In regards to telecommunications, a ‘port’ is a specific place - usually a socket - through which one device can be connected to another.
"PPE" is short for Personal Protective Equipment and refers to clothing, helmets, googles and other garments or equipment designed to protect the wearer from injury in hazardous or dangerous environments.
Proprietary IP telephones use a language specifically written by a phone manufacturer to use on its branded Cloud PBX. The advantage of Proprietary IP is that it is generally considered to have more features than it's open source counterpart Session Internet Protocol (SIP).
The public switched telephone network (PSTN) is the total of the worlds circuit based telephone network, allowing anyone in the world to connect to another. At its core, it is almost all digital, but it includes mobile as well as fixed telephones.
PSU is short hand for 'Power Supply Unit', which is the power block required on certain products to power the unit. There is a large number of products on the market that do not require these, as they can use 'Power over Ethernet' instead. Please see PoE for more info.
"PTZ" stands for "Pan Tilt and Zoom Camera" and is a is a camera that is capable of remote directional and zoom control.
Pushing this button will see the last number dialled from a telephone, redialled.
Also referred to as RADIUS (Remote Authentication Dial-In User Service), this protocol allows external servers to communicate with a business’s central sever, to request access to information, systems and/or services hosted on said central server.
Remote Voicemail Pickup
This functionality allows individuals to access voicemail messages they may receive while absent from their home/work environment, from other locations. Remote voicemail access may, or may not be, via a RADIUS.
This Shared Call Appearance (SCA) service allows a user to have several devices for the same contact number and services are shared on several phones and endpoints.
SCCP is an acronym for Skinny Client Control Protocol. SCCP is a Cisco proprietary standard for terminal control for use with VoIP. SCCP was first developed by the Selsius Corporation. The term "Skinny" refers to fact that SCCP is a simple and uncomplicated protocol that requires relatively little computer processing
Simplex refers to communication in one direction only. One device will transmit, while the other listens. On a handsfree phone for example, if both parties try to talk at the time, the line will go quiet, because the phone is unable to transmit simultaneously. To do this, you will need a Duplex device.
SIP is an acronym of 'Session Initiation Protocol' which is a communication protocol for sending voice and video over IP networks.
SFB or Microsoft Skype for Business
SFB is short for "Skype For Business". Skype for Business was formally know as Microsoft Lync (ML). "SFB" is a UC (Unified Communications) Platform that integrates common channels of business communications such as Instant messaging (IM), VoIP (Voice Over Internet Protocol), FTP, Web conferencing, Voice Mail (VM) and E-mail.
SNMP or "Simple Network Management Protocol" is an internet standard protocol for managing devices on IP networks. Common devices that support SNMP are modem racks, switches, severs, telephones, routers and printers.
SMART is short for "Smart Monitoring And Reporting Technology". SMART is a monitoring system that detects and reports on various indicators of drive reliability, SMART technology enable anticipation of hardware failures.
SNR is short for Single Number Rating, which is a value used for comparing the level of Noise Attenuation offered by ear defenders. The SNR value allows you to quickly compare the attenuation level offered by an ear defender. You simply substract the SNR value from the average noise level recorded in Decibels (dB) to get your "working" accoustic pressure. For example:
Noise Level recorded: 110dB
SNR Rating: 32
Acoustic Pressure: 110 - 32 = 78dB. Anything under 85dB is considered safe.
A softphone is a software-based telephone, most often utilising a PC and headset, which enables emulation of a Hardphone.
A sound card is hardware that can be added to a PC. These sometimes come with a PC, or can be added at a later date. They allow your Computer to handle sound more effectively, as well as letting other devices, such as headset, to connect to your PC.
Soundguard is the trademark name for the Plantronics 'Acoustic Shock Protection' technology. Please see 'Acoustic Shock Protection' for more information.
SOLAS Chapter II-2
SOLAS stands for "Safety of Lives At Sea" and is a maritime treaty which requires signatory flag states to ensure that ships flagged by them comply with the minimum safety standards in construction, equipment and operation. For ships constructed on or after 1st July 2014 a minimum of two two-way portable radios for each fire party for fire fighters communication must be carried on board. The two radio units must be explosive and or intrinsically safe
A telephone comprising a microphone and loudspeaker, allowing hands-free verbal exchanges.
Speakfocus is a Sennheiser technology which focuses on the user's voice to give clear sound even in noisy conditions.
A switch box is a device that sits between a telephone and a headset. It is very similar to an amplifier except it doesn't boost the audio signal. It does allow a user to easily switch between a headset and a handset though.
Talk time is the amount of time a telephone (or related accessory) can be used before its battery is exhausted and requires recharging.
Transmission Control Protocol (TCP) is one of the core protocols of IP. It checks for missing packets of data and the order of the packets between programs to ensure reliability.
Telephony Application Programming Interface
Telephony Application Programming Interface is a Microsoft Application Interface that allows computer telephony integration and enables your PC to use telephone services such as dialling and answering calls.
TMA or "Telephone Management Application" is a windows based software package used by Gai-Tronics products that allows you to remotely monitor the heath status of your SMART Telephones, program their functions and log and report on their stats - all over a standard telephone line.
UHF Stands for “Ultra High Frequencies”. UHF is International Telecommunication Union designated range of radio frequency electromagnetic waves between 300 Mhz and 3GHz (3,000 Mhz), also known as the decimetre band or decimetre wave.
A Uni-Directional Microphone can only pick up sound with high gain from a specific side or direction of the microphone. When using a Uni-Directional microphone the user must speak directly into the correct side or their voice will not be picked up. This is in contrast to Onmi-Directional Microphones which pick up sound equally from all directions of the microphone.
USB is an industry standard for a plug/connection between a PC and electronic device. This standard allows a connection which enables data communication and power to be transferred between the 2 devices. USB stands for 'Universal Serial Bus'.
There are a few different types of USB connectors. The most common are USB Type-A which is found on most PC's and interfaces. This is now being replaced by USB Type-C. These have a reversible plug, so it doesn't matter which way round you plug it in. More importantly, they can carry more power than the 5v achieved by USB Type-A, but are also closely intertwined with USB3.1, offering greater down speeds of up to 10Gbps (double the speed of USB3.0).,
VDSL / VDSL2
VDSL stands for “Very-High-Bit-Rate Digital Subscriber Line”. VDSL is a data communications technology that provides faster data transfer than ADSL over telephone lines. VDSL offers speeds of up to 52Mbit/s downstream and 16Mbit/s upstream. VDSL2 is the 2nd generation system and can exceed 100 Mbit/s simultaneously in both upstream and downstream directions.
VHF Stands for “Very high Frequency”. VHF is the International Telecommunication Union designated range of radio frequency electromagnetic waves from 30 MHz to 300 Mhz. Frequencies below VHF and denoted “HF” or High frequency, and frequencies higher than VHF are known as “UHF” or Ultra High Frequencies.
A virtual PBX (Private Branch Exchange) is a private telephone switchboard, hosted and managed by a telephone service provider on behalf of a business.
Please see ‘Auto Dial’.
Voice Clarity is the trademark name for Sennheiser HD Wideband audio. Please see Wideband.
Voice over Internet Protocol
This protocol allows human voices to be transmitted over the internet (in digital form) or other networks (in audible form), instead of via standard telephone lines.
A voice tube is a usually clear open ended microphone extension that helps headset microphones better receive any speech from the user.
VoIP is an acronym for ‘Voice over Internet Protocol’. Please refer to ‘Voice over Internet Protocol’ for more information.
A virtual private network (VPN) creates a private network connection across a public network, such as the Internet. This enables a PC or telephone to send and receive data across an open public network as if it was connected to a private network with all the security benefits.
WAV or " Waveform Audio File" is a file format by Microsoft and IBM for uncompressed or lossless compressed storage of audio data. It is also been known as a "WAVE" file
WDS stands for Wireless Distribution System. A WDS is a system enabling the wireless interconnection of access points in a network. It allows for a wireless network to be expanded by using multiple access points without the traditional requirement for a wired link to connect them together.
Wideband is an audio technology that allows audio telephony to be broadcast over a greater frequency range, which results in a clearer more natural sound. Wideband is accepted to cover the frequency range of 50–7,000 Hz.
Windsafe is the registered name for the Sennheiser microphone anti wind noise technology which helps sound quality when speaking outside in blustery conditions.
A WLAN or “Wireless Local Area Network” links two or more devices use some wireless distribution method, and usually providing a connection through an access point to the wider Internet. Most modern WLANs are based on IEEE 802.11 standards, marketed under the Wi-Fi brand name.
The Whisper Off-Hook Call Announce (WOHCA) feature allows you to call via intercom to another 7400 Series phone user who is engaged on a private call. The facility enables you to provide information to the user on your exchange, without disturbing the other caller.
A Y cable is a headset splitter used for training purposes. A Y cable allows 2 headsets to be connected to one telephone. The Y cable will usually have a little switch in it that allows either one or both people to speak on the line at once. Both headsets can hear of course.
Zero Touch Provisioning
When using certain IP/SIP phones, Zero Touch Provisioning can be used to quickly and easily get full configuration without having to manually provision the phone to your network.