Describing some commonly used professional radio communications terms


Address Resolution Protocol #
A TCP/IP protocol to query MAC address of the target device by its IP address, so as to ensure right communication services.
Adjacent Channel Selectivity #
A measurement of a receiver’s ability to process a desired signal while rejecting a strong signal in an adjacent channel.
Air Interface Encryption, an encryption method used in TETRA on the Air Interface signalling only (control signalling and user payload).
Air Interface #
In wireless communication, the air interface is the radio-based communication link between the mobile station and the active base station.
Antenna Feeder #
The RF cable connecting base station and the antenna. Usually, coaxial cable is used.
Application Programming Interface
Asynchronous Serial Interface #
A port for transmission of streaming data.
Attenuation #
The gradual loss in intensity of flux through a medium.
Authentication #
Authentication, also known as identity verification, is the act of confirming the validity of user identity.
Audio Distortion #
The deformation of audio signals occurs after modulation.
Automatic Vehicle Location


BS #
Base Station
Base Station #
In wireless communication, a base station is a wireless communication station installed at a fixed location and used as part of two-way radio system.
Bit Error Rate #
The number of received bits that have been altered due to noise, interference and distortion, divided by the total number of transferred bits during a studied time interval locking. A measure of the receiver's ability to resist the strong interference signals.
Bit Rate #
The number of bits that are conveyed or processed per unit of time. The greater the bit rate is, the more the data is transferred.
Busy Channel Lockout #
A radio feature. When it is enabled, any other user can not transmit on a busy channel.
Bit stream #
A continuous series of bits being transmitted over a communication channel.


Call Out #
Standardised paging and resource management method for TETRA systems.
Carrier #
Generally, carrier is a sine wave modulated to convey signal information. The frequency of the sine wave is higher than the bandwidth of the modulation signal as required. Otherwise, it brings about aliasing and distortion.
Close Circuit Television
Channel #
A channel refers to a transmission medium used to convey an information signal from a sender to a receiver.
Channel Associated Signalling #
A form of signalling to carry signalling information and voice signal in the same channel.
Channel Spacing #
The frequency difference between two adjacent channels.
Code Division Multiple Address #
A channel access method used by various radio communication technologies. It employs unique code sequence to establish the channel.
Coded Orthogonal Frequency Division Multiplexing #
The most advanced and promising modulation technology for the moment.
Code Rate #
The amount of bits being transferred per second, representing the bandwidth required for data transmission. The greater the code rate is, the wider the bandwidth is required and the more data is conveyed.
Compandor #
A radio feature. It can help improve signal-to-noise ratio of the system, thus reducing the background noise and obtaining good audio quality at the receiver.
Continuous Digital Controlled Squelch System #
Used to reduce the annoyance of listening to other users on a shared two-way radio communication channel. CDCSS mutes the speaker by digital encoding.
Continuous Tone Coded Squelch System #
Used to reduce the annoyance of listening to other users on a shared two-way radio communication channel.
Customer Programming Software


Dead Spot #
A zone within the radio transmitter where little or no radio signal can be received.
Digital Mobile Radio - Find out more about DMR
Digital Mobile Radio #
Digital Mobile Radio is a digital radio standard for professional mobile radio users developed by the European Telecommunications Standards Institute (ETSI) and authorised in 2005.
Dual Tone Multiple Frequency #
A type of signaling between telephone handsets and the switch in the telephone system, which is used to send the called number.
Direct Mode Operation
Direct Mode Operation #
Operational mode where radios are transmitting/receiving without using infrastructure.
Digital Signal Processor
Digital Voice Recording System - More information on DVRS


E2EE #
End to End Encryption
End to End Encryption #
Encryption method to encrypt the user payload (voice and SDS) independently of the network.
European Telecommunications Standards Institute


Five Tone #
A kind of signalling comprising 3 groups of signalling, each of which has five or more continuous audio signals. It can realise multiple functions such as Selective Call, Kill, Revive and etc.
Frequency Division Multiple Access #
A channel access method used in multiple-access protocols as a channelisation protocol. FDMA gives users an individual allocation of one or several frequency bands or channels.
Frequency Hopping #
A spread-spectrum technique to get much wider bandwidth by rapidly switching a carrier.
Frequency Response #
It refers to the way that the sound pressure and phase respond to different frequencies. As the audio signal in constant voltage output is connected with the system, the phase and the sound pressure from the speaker will change with different frequencies.
Full Duplex #
It refers to the transmission of data in two directions simultaneously. For example, a telephone is a full duplex device because both parties can talk at once.
Forward Error Correction #
A system of error control for data transmission, whereby the sender adds redundant data to its messages. This allows the receiver to detect and correct errors without the need to ask the sender for additional data.
Frequency Deviation #
The maximum instantaneous difference between an FM modulated frequency and the nominal carrier frequency.


Gateway Mode Operation #
Operational mode where a radio performs a “bridge” function between DMO and TMO.
Gateway Mode Operation
Group Call #
A call initiated to a group of members.
Global Positioning System - View our radios with GPS.
Global System for Mobile Communications


Half Duplex #
It provides for communication in both directions, but only one direction at a time. the two-way radio is a good example.
Home Channel #
The most frequently used channel.
HDC1200 #
The HDC1200 Signaling is compatible with MDC1200, and allows functions including PTT ID Encode & Decode, Kill & Revive Decode and etc.
HDC2400 #
The HDC2400TM signaling is exclusive to Hytera, and contributes to the system to achieve features including PTT ID, Kill, Emergency and etc.


ID #
Identity (numeric identifier)
Individual Call #
A call initiated to an individual user.
International Protection Rating #
Published by the International Electrotechnical Commission (IEC), it classifies the degrees of protection against the intrusion of solid objects, dust and water in electrical enclosures. IP rating consists of two digits where the first number indicates the level of protection against the ingression of solid objects and the second digit the level of protection against the ingression of liquids. The greater the number is, the higher the level of protection is. See our IP Ratings Guide to find the rating right for you.
IP #
Internet Protocol


Kill #
A radio feature. It can disable a lost or stolen radio remotely, preventing it from being used inappropriately.
Key #
A parameter that determines the functional output of a crytographic algorithm or cipher. Without a key, the algorighm would have no result.


Lone Worker #
A radio feature designed for persons who work alone. When it is enabled and a user does not operate his radio within a preset time period, the radio will alarm automatically to call for help.
Long Term Evolution - View our LTE handsets on the PoC / Broadband PTT section of the site.


Main Control Channel #
Time Slot in a trunked system used for control purposes
Man Down #
A radio feature. When this feature is enabled, the radio will alarm automatically to call for help if it falls over or stands aslant for a preset time period. For more detail, read our two way radio emergency features guide.
Main Control Channel
Media Access Control #
A sublayer of the logic link layer in a local area network. It provides addressing and channel access control mechanisms that make it possible for several terminals or network nodes to communicate within a multi-point network without any interferences.
Mobile Country Code #
A unique three-digit number that identifies each country.
Mobile Network Code #
A unique five-digit number that identifies a mobile phone operator/carrier.
Monitor #
A radio feature. It can reduce the conditions for receiving audio, but the background noise will increase accordingly.
Modulation Limit #
The ability of transmitter to prevent the modulation from exceeding the maximum deviation.


Network Management System - Learn more in our Network, Radio and Application monitoring and management guide.


Operation Code #
An instruction code that specifies the operation to be performed.
Over The Air Programming
Output Power #
The RF power to the antenna delivered by a transmitter.
Over The Air Programming #
Method whereby a part of the radios programming is changed using SDS messages from the “OTAP” application.


Private Branch Exchange (private telephone exchange)
Professional Mobile Radio - view our PMR section of the site for information on professional mobile technologies, frequencies and systems.
Public Switched Telephone Network
Press to Talk


Radio Frequency #
An electromagnetic wave frequency that can radiate to the space, ranging from 300KHz to 30GHz.
Remote Diagnostic and Control
Repeater Mode Operation #
Operational mode where radios are transmitting/receiving using a single repeater. These products are classed as repeaters
Reverse Display #
A radio feature. It enables the displayed information on the LCD to be rotated by 180 degrees.
Revive #
A radio feature. It can activate a killed or stunned radio remotely.
Repeater Mode Operation
Radio Register Service
RX #


Scan #
A radio feature. It allows a user to listen to communication activities on another channel.
Scrambler #
A radio feature. It can encrypt the audio signals to prevent eavesdropping.
Short Data Service
Selective Call #
A calling method that allows the calling party to select the specific called party.
Signalling #
The use of signals for controlling communications.
Squelch #
A radio feature. It acts to suppress the audio output of a receiver in the absence of a sufficiently strong desired input signal.
Stun #
A radio feature. It can remotely disable a radio. The stunned radio can transmit only.
Subnet Mask #
A 32 bit address, which divides the IP address into the network address and the host address.
Symbol Rate #
It is correlative with the quality of image transmission. Greater symbol rate achieves higher image transmission speed and image quality.
Signal-to-noise Ratio #
The ratio of signal strength to background noise, which is usually measured in decibels (dB). It is used to quantify how much a signal has been corrupted by noise.
Sensitivity #
The ability of a receiver to receive weak signals.
Spurious Response Rejection #
The capability of a receiver to receive a wanted modulated signal without exceeding a given degradation due to the presence of an unwanted modulated signal at any other frequency, at which a response is obtained.
Simplex #
It means the data can be transmitted in one direction only. For instance, TV broadcasting.


Talk Around #
A radio feature. It allows you to continue communication even when the repeater malfunctions, or when the radio is out of the repeater's range but within the coverage range of another radio.
Traffic Channel
Time Division Multiplex Access
Tetra Encryption Algorithm
TETRA Enhanced Data Service
As a professional mobile radio system based on time division multiple access, TETRA is an open standard developed by the European Telecommunications Standard Institute (ETSI) that describes a common mobile radio communications infrastructure throughout Europe.
Time-out Timer #
A radio feature. It is designed to prevent any user from occupying a channel for a long time.
Trunking Communication #
A communication technology with which many users can share a set of frequencies without affecting one another.
Two Tone #
A signalling comprising 2 kinds of audio signals. It can realise multiple functions such as Selective Call, Group Call and etc.
TX #


UI #
User Interface


Voice Operated Transmit #
A radio feature. With this feature, a user can transmit just by speaking into the microphone without the need to press PTT key.
VoIP #
Voice over Internet Protocol
Vehicle Professional Unified Communication


Whisper #
It allows your voice to be heard clearly even if you speak in a low voice.
White-box Testing #
White-box Testing, also known as structural testing and logic-driven testing, is a software testing technique that tests internal structures and process of an application rather than the functions.


Extended Pseudo Trunk - Learn more here
XPT Network Management System