Two Way Radio Glossary of Terms

Professional Radio Terms Glossary


API - Application Programming Interface.
AVL - Automatic Vehicle Location
Access Point (AP or Wireless AP) - A device that allows wireless devices to connect to a network. Access points act as a gateway between your devices and the internet and can be placed to extend the range of a wireless network.
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 - 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.
Attenuation - The gradual loss in intensity of flux through a medium.
Audio Distortion - The deformation of audio signals occurs after modulation.
Authentication - Authentication, also known as identity verification, is the act of confirming the validity of user or radio identity.


Base Station - In wireless communication, a base station is a wireless communication station installed at a fixed location and used as part of a 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.
Bitstream - A continuous series of bits being transmitted over a communication channel.
Breadcrumbs - Every time a GPS location is sent to the Dispatch application, these coordinates can be recorded and plotted on a map to show the travel route a mobile radio makes.
Broadband - Commonly refers to high-speed Internet access that is always on and faster than the traditional dial-up access. PoC radios use broadband internet access to communicate locally and nationally.
Busy Channel - Lockout A radio feature, that when it is enabled, any other user cannot transmit on a busy channel.


CPS - Customer Programming Software.
Carrier - Generally, the 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.
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.
Compandor - A radio feature that can help improve the 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 (CDCSS) - 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.


Dead Spot - A zone within the radio transmitter where little or no radio signal can be received.
Digital Mobile Radio (DMR) - Digital Mobile Radio is a digital radio standard for professional mobile radio users developed by the European Telecommunications Standards Institute (ETSI) and authorized in 2005.
Digital Signal Processor (DSP) - A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing.
Direct Mode Operation (DMO) - Operational mode where radios are transmitting/receiving without using the infrastructure.
Dispatch - An application that enables instant nationwide group or individual communication (voice, video, text) and supplies GPS location tracking of remote workers along with other functions like breadcrumbs and geofencing.
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.


End to End Encryption (E2EE) - Encryption method to encrypt the user payload (voice and SDS) independently of the network.
European Telecommunications Standards Institute (ETSI) - The European Telecommunications Standards Institute is an independent, not-for-profit, standardization organization in the telecommunications industry (equipment makers and network operators) in Europe, headquartered in Sophia-Antipolis, France, with worldwide projection.
Evolved Multimedia Broadcast Multicast Services (eMBMS) - For broadcast transmission across multiple cells, it defines transmission via single-frequency network configurations. The specification is referred to as Evolved Multimedia Broadcast Multicast Services (eMBMS) when transmissions are delivered through an LTE (Long Term Evolution) network.
Extended Pseudo Trunk (XPT) - Developed exclusively by Hytera, the Extended Pseudo Trunking (XPT) system is based on the ETSI DMR Tier II Conventional Standard and adds capabilities normally found in higher cost Tier III trunking systems. XPT makes DMR Tier II repeater systems more efficient to provide more channel capacity and adds valuable new features without the purchase of additional radio infrastructure hardware.


Five Tone - A kind of signaling comprising 3 groups of signaling, each of which has five or more continuous audio signals. It can realize multiple functions such as Selective Call, Kill, Revive and etc.
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.
Frequency Division Multiple Access - A channel access method used in multiple-access protocols as a channelization 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.


GPS  - Global Positioning Satellite – an accurate worldwide navigational and surveying system based on an array of orbiting satellites to fix the location of a radio receiver.
Gateway Mode Operation (GMO) - Operational mode where a radio performs a “bridge” function between DMO and TMO.
Geofencing - A virtual perimeter built around a specific geographic location in the Hytera Dispatch application. An alert can be sent to Dispatch when a radio leaves or enters one of these areas.
Global System for Mobile Communications (GSM) - GSM (Global System for Mobile communication) is a digital mobile network that is widely used by mobile phone users in Europe and other parts of the world. … GSM digitizes and compresses data, then sends it down a channel with two other streams of user data, each in its own time slot.
Group Call - A call initiated to a group of members. 


ID - Identity (numeric identifier). 
Individual Call - A call initiated to an individual user.
International Protection (IP) 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. An 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. Learn more about IP Ratings.
Internet Protocol (IP) - Set of rules governing the format of data sent over the internet or other network, for example, HTTP.


Key - A parameter that determines the functional output of a cryptographic algorithm or cipher. Without a key, the algorithm would have no result.
Kill - A radio feature that can disable a lost or stolen radio remotely, preventing it from being used inappropriately. Also known as Stun.


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. Learn more about two-way radio safety features.
Long Term Evolution (LTE) - Long-Term Evolution is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM/EDGE and UMTS/HSPA technologies. It increases the capacity and speed using a different radio interface together with core network improvements.


Main Control Channel - Time Slot in a trunked system used for control purposes.
Man Down - A radio feature, that when is enabled, the radio will alarm automatically to call for help if it falls over or stands aslant for a preset time period. Learn more about two-way radio safety features.
Media Access Control - A sub-layer 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 multipoint network without any interference.
Mobile Network Code - A unique five-digit number that identifies a mobile phone operator/carrier.
Modulation Limit - The ability of the transmitter to prevent the modulation from exceeding the maximum deviation.


Output Power - The RF power to the antenna delivered by a transmitter.
Over The Air Programming (OTAP) - Over-the-Air programming (OTAP) refers to various methods of distributing new software, configuration settings, and even updating encryption keys to devices like mobile phones, set-top boxes or secure voice communication equipment (encrypted 2-way radios).


PABX - Private Branch Exchange (private telephone exchange).
PMR - Professional Mobile Radio is a general term for digital two-way radios and is typically used outside the United States, where the term LMR or Land Mobile Radio is used.
Public Switched Telephone Network (PSTN) -  The public switched telephone network (PSTN) is the aggregate of the world’s circuit-switched telephone networks that are operated by national, regional, or local telephony operators, providing infrastructure and services for public telecommunication.
Push-to-Talk (PTT) - Push to Talk, or Press to Talk, is the ability to a make a radio call with the push of a button.
Push-to-Talk over Cellular (PoC) - PTT communications based on the 4G/LTE network of nationwide Mobile Network Operators like AT&T and T-Mobile. Learn more about PoC.


RRS - Radio Register Service.
Radio Frequency - An electromagnetic wave frequency that can radiate to the space, ranging from 300KHz to 30GHz.
Radio over IP - RoIP is PTT over internet protocol. Radio signals are transmitted via internet connections over satellite, LTE, or private networks.
Receive (RX) - Receiving communications data on a two-way radio.
Repeater Mode Operation (RMO) - Operational mode where radios are transmitting/receiving using a single repeater.
Revive - A radio feature that can activate a killed or stunned radio remotely.


SIM Card - Is a smart memory card inside a mobile phone or PoC radio, carrying a unique owner identification number and allows for a connection to a specific mobile network.
Scan - A radio feature that allows a user to listen to communication activities on another channel.
Scrambler - A radio feature that can encrypt the audio signals to prevent eavesdropping.
Selective Call - A calling method that allows the calling party to select the specific called party.
Sensitivity - The ability of a receiver to receive weak signals.
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.
Signaling -The use of signals for controlling communications.
Simplex - It means the data can be transmitted in one direction only. For instance, TV broadcasting.
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.
Squelch - A radio feature that acts to suppress the audio output of a receiver in the absence of a sufficiently strong desired input signal.
Stun - A radio feature that 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. A greater symbol rate achieves higher image transmission speed and image quality. 


TETRA - 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.
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.
Time Division Multiplex Access (TDMA) - Time-division multiple access is a channel access method for shared-medium networks. It allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using its own time slot.
Time-out Timer - A radio feature designed to prevent any user from occupying a channel for a long time.
Transmit (TX) - Transmitting or sending call information from a radio.
Trunking Communication - A communication technology with which many users can share a set of frequencies without affecting one another.


User interface (UI) A graphical screen that displays and provides functionality control of a device.


VoIP - Voice over Internet Protocol.
Voice Operated Transmit (VOX) - A radio feature that enables a user to transmit just by speaking into the microphone without the need to press PTT key.


Wi-Fi - Short for Wireless Fidelity and refers to the ability of Wi-Fi devices, such as laptops or PoC radios, to communicate on a wireless network within the range of one another.

We are here

To Help You!

Contact Us