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 Headset terms are used differently, or are closely related, within the industry. Instead of repeating definitions within the glossary, we have linked these to related terms, where relevant.

It is hoped this resource will help you making your purchase, but should you require further advice, please feel free to contact our friendly staff.

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1 Eared

A headset with one earpiece. See Monaural for definition.

2 Eared

A headset with two earpieces. See Binaural for definition.


2.5mm plugs are standard round plugs. Commonly used on mobile and cordless phones as well as a few business telephones.


3.5mm plugs are standard round plugs. Less commonly used than the 2.5mm plugs, these are used on some business telephones.


"A2DP Stands for "Advanced Audio Distribution Profile". This is a profile that defines how multimedia audio can be streamed from one device to another over a Bluetooth connection.


ActiveGard is the Sennheiser Trademark name for 'Acoustic Shock Protection'. See Acoustic Shock Protection for more info.


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.


ASP is short foo 'Acoustic Shock Protection'. Please see Acoustic Shock Protection for more information.


ATEX approved equipment has been specially designed and tested to work in explosive and dangerous atmospheres.


Attenuation is the noise level that is removed from your environment, allowing you to work safely in high noise areas. There are three levels of protection:
Low attenuation Low Attenuation
Allows you to work in areas of exposure to noise levels between 87db(A) and 98db(A).
medium attenuation Medium Attenuation
Allows you to work in areas of exposure to noise levels between 94db(A) and 105db(A).
High attenuation High Attenuation
Allows you to work in areas of exposure to noise levels between 95db(A) and 110db(A).


Binaural is used to describe a headset with two ear ear pieces.


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.


BLF stands for 'Busy Lamp Field'. A Busy lamp field is a row of programmable keys that indicate whether a colleagues phone line is busy or not, usually by the use of a colour LED.


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.

Connection Cord

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

Convertible Headset

A "Convertible" headset is a headset that can be worn in more than one wearing style. That is you can convert from one to another, depending on your preference. This usually means "Over the head" and "Over the Ear", but some headsets also offer a neckband option to.


DECT stands for 'Digital Enhanced Cordless Telecommunications'. Please see Digital Enhanced Cordless Telecommunications.

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.


This is a portable device that typically plugs into a parallel, or USB, port. Dongles grant access to wireless broadband or the use of protected software.


DSP is an acronym of 'Digital Signal Processing'. Please see Digital Signal Processing for for information.

Dynamic Noise Reduction

"Dynamic Noise Reduction" or "DNR" is an unpatented technology that allows up to 10db of noise reduction from any audio signal.


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

Ear Cushion

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 donut shaped.


EHS is an acronym for 'Electronic Hook Switch'. Please see Electronic Hook Switch for more information.

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.

FM Radio

These headsets have an inbuilt FM radio, which means you do not need a 3rd party device.

Handset lifter

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

HD Voice is the trademark name for Plantronics Wideband audio. Please see Wideband.

Headset Port

A headset port is a dedicated socket on your telephone to which you can connect a telephone headset.

Hunting / Shooting

These are designed for shooting care of the slim cups and correct attenuation levels for huntsman / marksman.


LCD stands for 'Liquid Crystal Display'. This is a flat panel display that uses the modulation property of liquid crystals with light.

Microsoft Lync

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.
This has now been replaced by Skype for Business

Microsoft Office Communicator

Microsoft Office Communicator is the former name for 'Microsoft Lync'. See Microsoft Lync for more information.
This has now been replaced by Skype for Business


MOC is an acronym of 'Microsoft Office Communicator' which is now known as 'Microsoft Lync'.


Monaural is used to describe a headset with one ear piece.


NC is an abbreviation of 'Noise Cancelling'. Please see Noise Cancelling for more information.


Neckband refers to the position headset is worn when in use. The neckband wearing style is worn around the neck.

Noise Cancelling

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.


NIB stands for "Natural Interaction Behavior" and enables face to face communication in noisy environment, without the use of an external communication radio

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.


PMR is short for Private Mobile Radio. PMRs are field radio communications systems which use portable, mobile, base station and dispatch console radios.

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)


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.


"PTT" Is short for Push To Talk. PTT is a common feature on 2 way radios


QD stands for ‘Quick Disconnect’. Please see ‘Quick Disconnect’ for more information.

Quick Disconnect

Quick Disconnect is a plug that connect a wired headset to it's connection lead. they are a identical flat plugs that simply click into each other.

Skype for Business

Microsoft Skype for Business (formerly Microsoft Office Communicator and 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.


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.

Sound Card

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.

Switch Box

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.


UC stands for unified communications. UC is the incorporation of real time communications services, this would include IP telephony, video conferencing, data sharing, instant messaging etc.

Ultra-Noise Cancelling

Ultra-Noise Cancelling microphones are simply more powerful 'Noise Cancelling' microphones. Please see 'Noise Cancelling' for more info.

Uni Directional

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'

Voice Clarity

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.

Voice Tube

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.


VOX is short for Voice operated exchange. This is a switch that operates when a sound over a certain level is detected. VOX is often used in Private Mobile radios to enable Handsfree features.


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.


Windsmart is the registered name for the Plantronics advanced anti wind noise technology with 3 layers of wind protection.


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.