Skip to main content



Accessory #

A TETRA radio accessory is a device that can be added to another device in order to make it more useful, versatile, or attractive, for example an headset or handheld microphone connected to a radio.

AI #

Air Interface.

Air Interface Encryption (AIE) #

Encryption on the air interface that is the vulnerable link between a base station and radio.

Airwave Network #

The Airwave Network is the UK Public Safety TETRA Network.

Ambience Listening (AL) #

A supplementary service in TETRA to allow an authorised user, for example a dispatcher, to remotely switch the mobile station into transmit mode and monitor its environment without the intervention of the mobile station user.

Antenna #

A conductor by which electromagnetic waves are sent out or received, consisting commonly of a wire or set of wires.

Also known as an 'aerial'. Use this term when referring to the aerial on Sepura radio and mobile products.

Antenna diversity #

One of several wireless diversity schemes that uses two or more antennas to improve the quality and reliability of a wireless link. Often, especially in urban and indoor environments, there is no clear line-of-sight (LOS) between the transmitter and the receiver, so the signal is reflected along multiple paths before being received. Each bounce of the signal can introduce phase shifts, time delays, attenuations, and distortions that can destructively interfere with one another at the aperture of the receiving antenna. Also known as 'space diversity'.

Application Programming Interface (API) #

A set of functions and procedures that allow the creation of applications which access the features or data of an operating system, application, or other service.


ATmosphere EXplosive. An international approval for products that are deemed intrinsically safe in certain environments where there is a risk of explosions, such as mining environments.

Authentication #

A security mechanism in TETRA, based on the challenge response between the mobile station and the infrastructure, in order to ensure the legitimacy of each party.

Automatic Person Location System (APLS) #

A map-based system in a (mobile) control room which displays the location of mobile human users.

Automatic Vehicle location System (AVLS) #

A service or application showing the location of a vehicle, either in terms of its geographical coordinates or by its location on a map.


Base Station #

A wireless transceiver at a fixed location, for example located within a control centre or hub, used by Airports, Police Stations, and Hospitals, that forms part of a wireless communications network. Typically, the base station connects to the radios within its area and relays the calls to the wired network. Base stations help direct "traffic" of two way radio and land mobile radio system users in the field.

Batch #

The definition of the software configuration in Radio Manager and the radios that make up a programming task.

Battery #

A device that generates an electrical current to power a device such as a radio. There are numerous types of batteries that offer varying longevity and power outputs.

Battery charger indicators #

On Sepura radios, the battery charge indicators are shown on the Home screen. The charge indicators comprise a bar that displays the charge level of the battery and a battery icon. A fully charged battery is indicated by a full bar next to the battery icon.


Bit error rate. Indicates the percentage of incorrectly received bits.

Blue LED #

A blue coloured LED on a Sepura radio that alerts the user of a missed event such as an incoming call or text message. Also known as the 'Missed Event Alert'.

Bluetooth® #

A wireless technology that allows voice and data connections between a wide range of mobile and stationary devices through short-range digital two-way radio. For instance, it specifies how mobile phones, Wireless Information Devices (WIDs), computers and PDAs interconnect with each other, with computers, and with office or home phones.

Optional Bluetooth allows users of Sepura handheld radios to make use of the many Bluetooth accessories available on the commercial market.

Bluetooth® pairing #

The process by which two Bluetooth® enabled devices are installed so that they communicate with one another. When communication is established, the joining of devices is called a 'trusted pair'.

Body-clip #

A clip on the back of a Sepura radio that allows the radio to be worn on clothing, a body vest or attached to a belt.

Body-worn #

A term used to describe the wearing of a radio on clothing or attached to a belt. The radio has an optional belt clip for attaching to the body clip on the back of the radio.

Body-worn video (BWV) #

Cameras that record high-definition video and sound worn on the body of a police officer, or other front-line workers, to record events. The cameras are usually very small and attached to the lapel of a jacket.

Broadcast call #

A half duplex point to multi-point call where communication is uni-directional from the calling to the called users. An alerting process is not required and the called users are not allowed to transmit back.


Cancel/Home key #

On Sepura radios this is a red key which you press to cancel a function or a call. Press and hold to return to the Home screen.

Carrier #

A radio channel that carries one or more communication channels.

Channel selector knob #

On Sepura radios, a knob which can be rotated to change channel.

Channel spacing #

The spacing between two adjacent radio channel frequencies.

Channel surveillance #

The monitoring of signal strength against a pre-determined threshold level in order to decide if Direct Mode Operation (DMO) may be allowed.

Circuit Mode Data (CMD) #

A method for data transmission where a continuous connection is required for the lifetime of the session to transmit all the data in a complete burst as opposed to Packet Data where the data can be split into sections or packets.

Clear Voice Override (CVO) #

Switching from encrypted to clear voice.

Client GUI #

The graphical user interface component of the Radio Manager Programming Client. Allows users to monitor and control the updating of connected radios. Also see Client Service and Programming Client.

Client Service #

The Windows service (Sepura Programming Client Service) component of the Radio Manager Programming Client which downloads Programming Client software updates and programming batches which are used to reprogram connected radios.


Calling Line Identity.

Colour codes #

A system used by some digital radio networks to identify the radios within that network. In TETRA colour codes are used to identify base stations.

COM port #

A physical or virtual serial port on a computer.

Common Cipher Key (CCK) #

Used to protect group downlink calls in class 3 systems.

Connector Protection #

A Sepura feature that allows a radio to be used in a salt water environment or an area with high salt laden humidity (for example sea mist/fog) without potential risk of corrosion to the connector.

Context key #

User-programmable key on a Sepura radio that can be customised to provide a shortcut to a menu option, such as the Contacts list or Talkgroups. Radios may typically have left, centre and right context keys.

Context key options #

Options that appear on the radio's display above the context keys showing the selectable short-cut when either key is pressed.

Context menu #

A menu related to a specific item on the user interface, usually displayed by right-clicking on the item.

Control Channel (CCH) #

A channel that is used for sending and receiving data, and managing messages such as cell reselections and authentication.


Commercial off-the-shelf.

Covert #

A term used to describe operations (namely by police) that are not openly acknowledged. They are sometimes also referred to as 'undercover operations'. Some Sepura products are designed for covert operations.

Covert secret, hidden #

Usually refers to type of equipment, such as covert radios, for use with agencies involved in surveillance and undercover

Covert Mode Operation #

An operating feature on Sepura radios that turns off all visual alerts such as the backlight and adjusts the microphone sensitivity to allow 'whisper operation'. It also reduces the level of the loudspeaker if an earpiece is not being used. If the radio has a vibrator alert enabled then this will also be deactivated.

Crypto Management Centre (CMC) #

Sepura software used to generate and manage end-to-end encryption keys.

Customisation #

A set of parameters and values that are used to configure a radio to suit the user's requirements. Do not use the term 'configuration' when referring to the programming of a radio.

Calling Line Identity (CLI) #

A function that allows the ISSI or phone number of the incoming caller to be displayed on the radio.

Callout #

A feature which allows a controller to contact radios to inform them of an incident. It allows the radio users to indicate acceptance or rejection of the Callout alert and to receive further information about it.


DC #

Direct Current.

Derived Cipher Key (DCK) #

An encryption key used for Air Interface Encryption (AIE) in Class 3 systems. This key is produced as a result of authentication, and is used for uplink and one-to-one messages.

Dialling #

The exchange mechanism between the user and the radio when performing the act of entering numbers to make a call to another radio user or telephone user.

Digital Mobile Radio (DMR) #

Digital mobile radio (DMR) is an open digital radio standard for professional mobile radio (PMR) users specified in the European Telecommunications Standards Institute (ETSI) Standard TS 102 361 parts 1-4 and used in products sold in all regions of the world.

Digital Mobile Radio Association (DMR Association) #

A global organisation focused on helping to make DMR the most widely supported 21st Century digital radio standard for the business world. The DMR Association was first set up in 2005 as the DMR-MOU Association by a group of leading public mobile radio manufacturers to support ETSI during the DMR standardisation process. The DMR Association is open to any organisation or individual interested in using or building DMR products or in supporting the DMR standard in other ways. The Association maintains links with regulators, trade bodies and standards organisations around the world.

Direct Mode Operation (DMO) #

The facility for TETRA radios to communicate directly with each other without using the TETRA infrastructure. Also referred to as half duplex operation (one user talks at a time).

Discreet listening #

A TETRA supplementary service enabling an authorised user like a dispatcher to covertly (secretly) monitor the calls in progress.

Dispatcher #
  1. Job title of a person who dispatches resources to locations, such as those working in control centres for Police, Fire and Ambulance resources.
  2. A name sometimes given to a software application designed to assist users to dispatch resources to various locations.
Display #
  1. An electronic device for the visual presentation of data and images.
  2. A term used to refer to the LCD on the radios and mobile transceivers.
DMO gateway / Direct Mode Operation gateway #

A device that allows users working in Direct Mode Operation to communicate with users in Trunked Mode. This is often used to extend the working range of a radio.

DMO repeater / Direct Mode Operation repeater #

A radio acting as a repeater provides a service to other radio users. It extends the range and enhances the reliability of Direct Mode communication compared with basic direct communication between the radios.


Dial-Up Network. Bluetooth® support of packet data sessions.

Duplexer #

A device that allows the repeater’s receiver and transmitter to operate from a single antenna. When operating within neighbourhoods where other RF devices are installed, including broadcast antennas and microwave link transmitters, the duplexer prevents interference with other RF devices.

Dynamic Group Number Assignment (DGNA) #

A supplementary service defined in the TETRA standards which is used for dynamic management (creation and dissolution) of user talkgroups.


Encryption #

A method for coding/ scrambling the information (voice or data) so that it cannot be understood or deciphered without special equipment or software.

Encryption key #

A pseudo random number that is used in an encryption algorithm to encrypt data.

End-to-End Encryption (E2EE) #

Encryption of the total communication link (from one end to the other) without intermediate decryption, required for maximum security.

Ethernet #

A family of network protocols based on asynchronous frames. The Ethernet framing structure provides a flexible payload container with basic addressing and error detection mechanisms.

European Telecommunications Standards Institute (ETSI) #

A European standards organisation that produces global standards for Information and Communications Technologies including TETRA for fixed and mobile radios, broadcast, internet and so on.

Emergency Button #

A button, usually located on the top of a radio by default, that is programmed to initiate an Alarm Call.



Fast Associated Control Channel. A channel used for sending and receiving data during a voice or packet data call.

Fast Access Box #

A component of the Home screen on a Sepura radio GUI that displays the selected talkgroup and folder (unless the talkgroup was selected form the All folder).


Federal Communication Commission. (U.S. telecommunications regulator ).

Fist microphone #

A handheld microphone that is usually connected to a mobile radio within a vehicle, but can also be used with a desk mounted mobile radio. Mainly used to initiate group calls, some Fist microphones have keypads allowing users to make private calls.

Fleet #

A set of subscribers organised into a closed user group who can communicate using a private numbering plan operated within an FSSN domain.

Fleet Management #

a) The activity performed by a resource to manage the radios and other assets. b) Term used in Radio Manager to describe the process of entering and maintaining the TEI and ISSI numbers for a fleet of radios, and the mappings between them.

Fleet Specific Short Number (FSSN) #

A private number of up to 6 decimal digits allocated to a subscriber to enable short number dialling to other members of the same FSSN domain. An FSSN enables intra and inter-fleet dialling within each FSSN domain. The same FSSN number space can be re-used in every FSSN domain.

Full duplex #

A channel providing simultaneous transmission in both directions, allowing both parties to speak and listen at the same time.

Full duplex call #

A full duplex call is when both parties can talk simultaneously. Also referred to as a 'private call'.



This is a 24 digit number identifying the talkgroup.

Gateway #

A device which interfaces the TETRA network with other private or public telecommunications networks, such as PSTN and ISDN. See also DMO gateway and GMO.

Global Positioning System (GPS) #

An accurate worldwide navigational and surveying facility based on the reception of signals from an array of orbiting satellites.

GoS #

Grade of Service, used to specify the level of access on a radio network.

Graphical User Interface (GUI) #

a) A visual way of interacting with a computer using items such as windows, icons, and menus, used by most modern operating systems. b) A term used to describe the software component of Radio Manager that modifies the contents of the database.

Group #

A set of individual subscribers for which a GTSI is defined. The group is assigned a unique GSSI, which maps to the

set of ISSIs. The GSSI is used to address the entire group during signalling. Individual subscribers can be members of more than one group and groups can be dynamically created, edited or deleted.

Group call #

A call made by one radio user to other users within a nominated talkgroup. Groups are set up on the radio (also known as talkgroups) that contain other radio users either performing a similar role or who are within a distinct location. This type of call is initiated when the user presses the PTT button on the radio. Only one person can talk at any time during these calls.

Group Cipher Key (GCK) #

A key used in conjunction with CCK to give crypto group separation between groups. Allocated to specific talkgroups for downlink group calls.

Group Cipher Key Number (GCKN) #

Used for associating TMO talkgroups to Air Interface Encryption keys.

Group Short Subscriber Identity (GSSI) #

Short form TETRA group identification number.

Group TETRA Subscriber Identity (GTSI) #

The long form TETRA group identity. The long form of group identity consists of the radio's Mobile Country Code (MCC), the Mobile Network Code (MNC) and the Group Short Subscriber Identity (GSSI).


Half duplex #

A system that only allows the transmission of a radio signal in either direction, but not simultaneously. Meaning, only one person can speak and one (or more) people can listen at any given time. The majority of two-way radios only provide half duplex communication.

Half duplex call #

A call made by a radio user, initiated by pressing the PTT button, to other users within the talkgroup. The PTT button is released to listen and allow another user to talk. See half duplex.

Handheld #

A term used to describe a device that can be operated when held in the hand.

Handover #

Switching an on-going call to a different channel or cell in a wireless cellular network. Also known as 'handoff'.

Hand-portable #

A device that is operated whilst being held in the hand or bodyworn. Do not write as 'hand portable'.

Handset Based Console (HBC) #

A telephone style handset with built in display used to control Sepura mobile radios and gateways. If followed by a number (e.g. HBC3) this refers to the variant.

Haptic(s) #

Haptic technology, haptics, or kinesthetic communication, is tactile feedback technology which recreates the sense of touch by applying forces, vibrations, or motions to the user.

Headset #

A device that provides a mechanism of listening to audio whilst worn over the head. Such devices usually have two earpieces, although some specialist headsets can deliver audio to one ear.

Home network #

A network where a subscriber has a direct subscription. This means that a subscriber identity has been allocated in advance of any network access.

Home screen #

The top level screen which appears when the radio powers on, and when it is idle.

Hooking call #

A call that needs to be accepted by the other user rather than a call which just drops in.


Headset Profile, a Bluetooth support for a headset.


HyperText Markup Language, a coding language used to create web pages.


Hypertext Transfer Protocol.

Human Machine Interface (HMI) #

Any device that interacts between a human and machine such as a keypad, computer mouse etc. On Sepura radios the HMI is the radio's display and keypad.


Inter-System Interface #

An open interface standard used to connect two TETRA networks together.


Interoperability (of TETRA equipment).


Istituto Superiore delle Comunicazioni e tecnologie dell'Informazione, the current certification body for TETRA IOP.


The objective of the IECEx System is to facilitate international trade in equipment and services for use in explosive atmospheres, while maintaining a required level of safety. 'Ex' areas can be known by different names such as 'Hazardous Locations', 'Hazardous Areas', 'Explosive Atmospheres', and relate to areas where flammable liquids, vapours, gases or combustible dusts are likely to occur in quantities sufficient to cause a fire or explosion. The modern day automation of industry has meant an increased need to use equipment in Ex areas. Such equipment is termed 'Ex equipment'.

Inbox #

Where incoming messages are displayed in a Sepura radio. When the Inbox is full, unsaved older messages are automatically deleted when new messages are received. If you want to keep a message, you must save it.

Infrastructure #

Base stations, switches, links, and various management equipment that form the network of equipment that enable radios and mobile radios to operate over a particular geographical area.

Individual Short Subscriber Identity (ISSI) #

Individual number of a TETRA radio.

Individual TETRA Subscriber Identity #

A combination of the Mobile Country Code (MCC), the Mobile Network Code (MNC) and Individual Short Subscriber Identity (ISSI) equal the ITSI.


K #

Authentication K value. Hex number used for authentication purposes (AIE).


Key Association Group. Used for associating DMO talkgroups to Air Interface Encryption keys.

Key Encryption Key (KEK) #

Encryption key used to encrypt other keys sent to the radio (E2EE).

Key Management Centres (KMC) #

An entity for remotely loading keys to user terminals.

Keypad #

A set of buttons arranged in a block or pad that have either digits, symbols or alphabetical characters on, or a combination of all of these.

Keypad lock #

A function on a device, such as a mobile phone or computer, that prevents a user accidentally activating functions using the keypad or to prevent access to the functions for security reasons.

Keystream #

Pseudo random data derived from KSG, used to mix with plain text data to produce encrypted data stream.

Keystream generator (KSG) #

Produces a key stream from inputs of encryption key and synchronisation vectors fed into the encryption algorithm.


Lone Worker #

Lone Worker periodically checks the user's status, calling for help if the user becomes incapacitated. Ideal for health workers, maintenance staff or other employees working in isolation, it can be configured to send an emergency call or GPS co-ordinates if an emergency situation is detected.

Large mode #

A selectable mode of operation on a Sepura radio that increases the size of the displayed information on the user interface.

Late Entry #

A TETRA Supplementary Service which allows a user who has, for example, just switched Mobile Station or has finished another call, to join a call in progress between the members of their talkgroup.

Lawful Interception #

A facility for telecommunications networks like TETRA to be monitored and calls intercepted by government agencies.


Light Emitting Diode. An electronic component that emits light when it receives an electrical charge. Commonly written as the short form LED.

Left navigation key #

The Left navigation key is one of the keys on a Sepura radio which allows you to select options on the display.

Licence, license #

A key to enable the use of a software program.

Line Station (LS) #

A fixed, wireline user radio, as distinct from a mobile radio, connected to a TETRA network, providing services and facilities available to a mobile user but without the need to be in the operational range of the system.

Lithium-ion batteries #

A lithium-ion battery (sometimes Li-ion battery or LIB) is a member of a family of rechargeable battery types in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging.

Local Area Network (LAN) #
  1. A system for linking private telecommunications equipment within a building or cluster of buildings.
  2. A system for linking a number of computers, terminals and workstations together or to a mainframe computer in order to share data, printers, information programs and so on. Usually confined to a single building or office within a building. Ethernet and WiFi (802.11) are common examples.
Live microphone #

A microphone that is activated and provides uninterrupted commentary from the user. On TETRA radios it is usually associated with the use of the Emergency key on a radio which, when pressed, activates the microphone in order for the user to speak directly to the dispatcher or other radio users on the talkgroup.

Location Information Protocol (LIP) #

Format for sending GPS location data over a TETRA system.

Lone Worker #

A operating function of a radio, associated with a user profile, that allows a user working alone to indicate that they are safe. When the user selects the Lone Worker profile, the radio will periodically emit an audible alert. Each time the user hears the alert he or she must press a key on the keypad to prevent an alert being triggered. If no key is pressed within a given time, the radio will send an Emergency Status message to a customised location, for example to the Dispatcher. It can be configured to send an emergency call or GPS co-ordinates if an emergency situation is detected.

Low battery warning #

A warning on a Sepura radio that indicates when there is less than 12% of the charge left in the battery. The warning comprises a low battery icon and flashing of the red LED.


Man-Down #

An active, smart personnel monitoring system, Man-Down checks for abnormal lack of motion and raises an emergency call or sends an emergency message if the user becomes incapacitated.

Automatically adjusting to user movement, Man-Down offers motion and tilt monitoring, raising a local alarm in add to over-the-air alerting, and can be configured to send an emergency call or GPS co-ordinates.

Micro SD card #

Allowing up to 4GB of data storage, Micro SD cards make transfer, retrieval and organisation of data quick and easy. Data can be encrypted to safeguard your files and storage of WAP sites is also supported, permitting rapid look-up of data and images. SDS messages can include a shortcut to a WAP page either on the local Micro SD card, or to the backend WAP server. Radio Manager 2 may also be used to manage the WAP data encrypted and stored on the Micro SD card.

MNI - Mobile Network Identity #

This is 24-bit combination of MCC and MNC. It identifies the network code the talkgroup is valid for.

Main Control Channel (MCCH) #

Data signalling channel used for registration, cell reselection, data and so on, when the radio is not in a call.

Man-Down #

A operating function of a radio, associated with a user profile, that initiates an emergency signal when the radio is tilted at a nominated angle for a set duration of time. An active, smart personnel monitoring system, Man-Down checks for abnormal lack of motion and raises an emergency call or sends an Emergency Status message if the user becomes incapacitated. It can be configured to send an emergency call or GPS co-ordinates if an emergency situation is detected.

Master reset PIN #

An 8 digit secure PIN that is used to reset the security PIN on a Sepura radio.


Mobile Country Code, (part of TETRA Number Identity).

A list of commands and options displayed on a user interface.

The structure given to the list of commands and options as programmed into the user interface.

MicroSD card #

Allowing data storage, microSD cards make transfer, retrieval and organisation of data quick and easy. Data can be encrypted to safeguard files and storage of WAP sites is also supported, permitting rapid look-up of data and images. SDS messages can include a short-cut to a WAP page either on the local microSD card, or to the backend WAP server. Radio Manager 2 may also be used to manage the WAP data encrypted and stored on the microSD card.

Missed Event #

A term used to describe a missed incoming call or text message on a radio or mobile. On some Sepura radios and mobiles a blue LED illuminates when a missed event is registered on the device.

Missed Event Key #

A soft key on the radio or mobile radio that, is programmed, provides a list of missed events when pressed.


Mobile Network Code, (part of TETRA Number Identity).

Mode Key #

A key on a Sepura radio or mobile that activates various functions when pressed or when pressed together with the Navi-knob or Navi-keys.

Modified Group Cipher key #

The key used for downlink group calls when GCKs are used. Formed from GCK modified by CCK.

Motorbike Control Unit (MCU) #

Small Control Unit to control the radio when installed on a motorbike.

Mobile Station (MS) #

A TETRA radio, including handheld, mobile and fixed radios.


Multislot Packet Data, IP data service using multiple timeslots.

Mobile Network Identity (MNI) #

The MNI is broadcast by all TETRA radios to identify the network uniquely. It consists of a combination of the three digit Mobile Country Code (MCC) and the Mobile Network Code (MNC) assigned to each operator within each country.


Mobile Subscriber ISDN.


Mean Time Between Failure.


Mean Time To Repair.



Network Management Subsystem.

Noise Cancelling Microphone #

A noise cancelling microphone reduces ambient noise and makes speech more intelligible in voice transmission mode.

Normal mode #

A selectable mode of operation on a Sepura radio that displays the maximum amount of information available for display in a compact character size. Most radios are operated in normal mode.

Keys marked ‘+’ and ‘-‘ on a Sepura Handset Based Console, used instead of the Navi-knob present on Sepura TETRA hand-portable radios. The keys are used to adjust the speaker volume and select different modes of operation. Pressing or pressing and holding the '+' Navikey is equivalent to turning the Navi-knob clockwise and pressing or pressing and holding the '-' Navi-key is equivalent to turning the Navi-knob counter-clockwise.

A continuous rotating knob on a Sepura TETRA radio that allows the user to change talkgroups, select status messages, as well as controlling the speaker volume.

Four arrow keys (Left, Right, Up And Down) on a Sepura radio that allows users to choose menu options and navigate through the menus. The keys are located above the keypad.

National Radiological Protection Board (NRPB) #

The National Radiological Protection Board (NRPB) was a public authority in the UK created by the Radiological Protection Act 1970. Its statutory functions were to conduct research on radiological protection and provide advice and information on the subject to Government Departments and others. It was also authorized to provide technical services and charge for them. Originally NRPB dealt only with ionizing radiation, but its functions were extended in 1974
to non-ionizing radiation.



An independent regulator and competition authority for the UK.

Officer #

A generic term used for police, fire and security personnel.


Over the Air Key. Delivery of encryption keys for AIE via the TETRA Air Interface.


Over the Air Rekeying. Replacement of Cipher keys over the air to TETRA radios (E2EE). A TETRA facility which allows for change of the encryption keys in the radios to be done remotely over the air.



All Sepura terminals share a common Peripheral Equipment Interface (PEI) which meets ETSI standards and permits proprietary extensions of the AT command set, providing third-party applications and solutions with an interface into the radio's functionality.

Performance Monitoring #

Performance Monitoring enables third-party control room applications to monitor TMO network performance. Using specific Short Data Service (SDS) messages, terminals can be polled periodically to give a snapshot of network performance, providing data for the comparison of planned and actual network performance.


Public Automatic Branch eXchange.

Packet (Mode) Data. #

A mode of data transmission where data message is split into small 'chunks' or packets, transmitted packet-by-packet to the end destination (without a need for dedicated connection in between, as for circuit data), and assembled again in the correct order.


Public Access Mobile Radio.


Pulse Code Modulation.

Performance Monitoring #

Performance Monitoring enables third-party control room applications to monitor TMO network performance. Using specific Short Data Service (SDS) messages, radios can be polled periodically to give a snapshot of network performance, providing data for the comparison of planned and actual network performance.

Peripheral Equipment Interface (PEI) #

All Sepura radios share a common Peripheral Equipment Interface which meets ETSI standards and permits proprietary extensions of the AT command set, providing third-party applications and solutions with an interface into the radio's functionality. b) Connection point for peripheral equipment (RS232 port protocol on TETRA radios).

Personal Identity Number (PIN) #

A number used to access a radio (prompted on start up screen) and entered using the keypad.

Phonebook #

Where Sepura radios store contact details.

Picture message #

A small JPEG image file with an accompanying text message sent to recipients over the TETRA Air Interface.

Point-to-point call #

A half duplex call made to a contact on the network using the PTT button. Unlike a group call, a point-to-point call is a private call to an individual.

Point-to-multipoint #

Another term for a group call, where one user initiates a call to several users on a talkgroup using the PTT button.

Press and hold #

A term used to tell the user to press and hold a key on a keypad or keyboard until the device has changed state, for example, 'press and hold the Mode key to power off the radio'. The user only releases the key when the state has changed.

Programmable side button #

On a Sepura hand-portable radio, a button on the side of the radio whose behaviour can be programmed.

Programming Client #

Part of Radio Manager that interfaces to the terminals for programming new software and updating configuration parameters. Consists of a Client GUI and a Client Service.

Priority #

A service that in case of system congestion offers one or more levels of 'call queue jumping', to those users who are allocated it, on the basis that their communication needs or requests are deemed to be more important. The highest priority call is an Emergency call. 4 levels are pre-emptive.

Priority Group Scanning (PGS) #

Automatic switching to a talk group of a higher priority.

Privacy screen #

A customisable option so that if the screen is inactive for a period of time the display will be replaced with a customisable picture in order to protect the privacy of any displayed information. This is particularly useful for radios worn at shoulder level. The privacy screen will be replaced by the normal display if any activity occurs which turns on the backlight.

Private telephone call #

A full duplex call between two radio users where they can talk simultaneously.


Public Switched Telephone Network.

PTT button #

The button, usually on the side of the radio, pressed to initiate a half-duplex call. The button is released to listen to any response from other radio users.


Pin Unlocking Key.

Push-to-talk (PTT) #

A button, typically on the side of the radio or on the external headset, that when engaged activated the microphone for transmission. It is important to note that only one radio can transmit on any given radio channel at one time.


QoS #

Quality of Service.

Quick Call #

A special individual call configured on a soft key to request help or information from a pre-configured individual or talkgroup destination in a non-emergency situation.


RM Application Administrator #

A person who performs the administration of the Radio Manager application, performing tasks such as software upgrades, backups of databases and user administration.

RM Client Engineer #

A person who provides the services to connect the radios to the RM Programming Client. Also see Programming Client.

RM Template Administrator #

A person who implements the radio customisations, taking input from the fleet mapper definition and user authority. Responsible for the updates to customisation templates and designs and implements data structures based upon fleet map and user definitions.


Radio User Assignment.


Radio User Number.

Rugged Accessory Connector #

A side connector on the Sepura radios used for the connection of accessories and for programming the radio.

Rugged Side Connector (RuSC) #

A connector on the Sepura STP8x series radios used for the connection of accessories and for programming the radio.


Rugged Accessory Connector.

Radio #

A device that uses RF energy to transmit and receive voice and image data. Radios are often referred to as terminals.

Radio coverage #

The area within the broadcasting range of a base station or network and the ability to transmit and receive RF signals within that area. Coverage is dependent on the strength and quality of the radio signal strength.

Radio coverage indicators #

Radio coverage and the quality of the signal is indicated by a combination of an icon and a bar indicator displayed on the Home screen on a Sepura radio.

Radio Frequency Identification (RFID) #

A method for uniquely identifying an object using a tag or module that carries a unique ID number, or code. Identification can be made using wireless (RF or radiowave) connection, meaning no line-of-sight or physical contact is needed.

Radio Manager #

Software application used to create customisation scripts for Sepura TETRA radios.

Radio Manager Configuration (RMC) #

A file that contains all operating parameters that are uploaded from a radio.

Radio Manager Package (RMP) #

A file that contains software (firmware) and parameter definitions for a radio.

Radio Manager Script #

A file that can be used to repair, update or modify existing Radio Manager installations.

Radio Manager Template (RMT) #

Radio operating parameters defined within Radio Manager.

Radio Signal Strength Indicator (RSSI) #

A signal or circuit that indicates the strength of the incoming (received) signal in a receiver, for example the signal strength indicator on a cell phone display.

Reciever #

A circuit that accepts signals from a transmission medium which can be wireless or wired, and decodes or translates them into a form that can drive local circuits. For example, a radio receiver that detects and demodulates the signal from the airwaves or an ultrasonic receiver that turns ultrasound signals into electrical signals.

Registration #

The act of becoming an active and recognised TETRA user by exchange of ITSI with the SwMI (Switching and Management Infrastructure).

Remote Speaker Microphone (RSM) #

A speaker and microphone combination that is attached to the facility connector of a handheld radio.

Repeater Mode #

In Repeater Mode a radio enables two or more radios operating in DMO Mode to communicate over an extended range, automatically relaying voice and messages by operating as a repeater. See also DMO repeater.

RF #

Radio Frequency.

Right Navigation Key #

The Right navigation key is one of the keys on a Sepura radio which allows you to select options on the display.



SCADA (Supervisory Control and Data Acquisition) allows you to monitor remote equipment, tracking and protecting assets, as well as selecting and deploying resources based on location and status

Status-triggered functions #

Status-triggered functions allow remote control of a radio through unique status codes, which can activate one of 60 functions. Triggering is permitted from authenticated sources only and can be used to remotely control vehicle-based radios or to set operating parameters on temporary staff radios, limiting training time without compromising safety.

Status indicator #

a) A status indicator is usually an LED that illuminates to alert the user of a change of status. b) A tri-coloured LED on the Sepura STP series radios and mobile radios is used to identify a change of state, for example when switched to Transmit Inhibit the status LED flashes orange.

Status message #

Words or concise phrases selected from a pre-determined list that is resident in the terminal, which are transmitted as a simple code reference, and then de-coded by the receiving device and displayed as the word message, e.g. "At the scene".

Status service #

A mechanism to deliver short messages between user radios in compact form by transferring only an integer number with textual interpretation provided by the terminals, e.g. 09 could be interpreted as "off-watch", and 08 as "at the scene".

Status-triggered functions #

Status-triggered functions allow remote control of a radio through unique status codes, which can activate one of 60 functions. Triggering is permitted from authenticated sources only and can be used to remotely control vehicle based radios or to set operating parameters on temporary
staff radios, limiting training time without compromising safety.

Switching Mangement Infrastructure #

Refers to the entire TETRA network infrastructure.


Specific Absorption Rate.


Sepura Advanced Serial Interface.

Scanning #

The process of repeatedly tuning through a sequence of channels whether manually done by the user or automatically by the radio.


Sepura Colour Console. If followed by a number (e.g. SCC3) this refers to the variant.


Static Cipher Key.


Static Cipher Key Number.


Static Cipher Key Version Number.


Short Data Application.


Short data services (SDS) are TETRA transport services for the transmission of data. Messages can be sent and received by TETRA radios, dispatchers, and external applications. The parties are identified by 24-bit integer Short Subscriber Identities.

Search folder #

On Sepura radios, the Search folder allows you to search the entire phonebook for contacts and numbers.

Select/Send key #

A key on Sepura radios used to make a call, send a status or text message.


TETRA Association Security and Fraud Prevention Group.

SIM card #

A smart card inside a mobile phone, carrying an identification number unique to the owner, storing personal data, and preventing operation if removed.

Smart call #

On Sepura radios, a Smart Call is a call to an address other than the selected talkgroup.


Serial Port Profile, Bluetooth support of an RS232 serial port.

Secondary Control Channel (SCCH) #

An alternative (to the MCCH) data signalling channel used for registration, cell reselection, data etc.. when the radio is not in a call.

Secret key #

The unique key embedded securely in the terminal, which is used for authentication.

Security & Fraud Protection Group (SFPG) #

Industry group that has defined guidelines for the distribution of Encryption information.

Short data applications (SDA) #

Forms on the display on a Sepura radio from where SDS messages are sent.

Signalling Encryption Key #

Used to encrypt the message containing the traffic keys (E2EE).

Slow Access Control Channel (SACCH) #

Used for sending/receiving data when in a voice or packet data call and the uplink is used on the cell (by this radio or another one).

Smart menu #

The Smart menu feature allows fast access to many soft key features and functions in the radio. The Smart menu is accessed by pressing and holding a suitably customised soft key. Up to 20 Smart menus may be customised and each Smart menu may have up to 20 soft key functions available. The first item in the Smart Menu is highlighted when the Smart. (S)

Soft key #

A programmable key on a Sepura radio that can be customised as a shortcut to a function, for example a context key on the radio that can be customised as a shortcut to the Contacts list. On some radios, the Select/Send key and the Cancel/Home key, along with all 12 keys of the radio keypad (1 – 9, *, 0, #,), left- and right context keys, and the Emergency Key are programmable soft keys. (S)

Standalone Key Management System (SKMS) #

Creates and/or distributes ‘K’ values and Static Cipher keys for TETRA radios in AIE.

Static Cypher Key (SCK) #

Used for protecting Direct Mode transmissions where no authentication is possible, for class 2 systems and as a fallback key for use on base stations disconnected from the SwMI.

Static Cipher Key Number (SCKN) #

The number used for each SCK.

Static Cypher Key Version Number (SCK-VN) #

The version number used for each SCK.


Talking Party Identity (TPI) #

ISSI or telephone number of the talking party during a call.

Talkgroup folder #

Folders are used to organise a talkgroup list to speed up the selection of favourite groups on radios.


Traffic Channel.


Time Division Multiple Access.


TETRA Encryption Algorithm.


Traffic Encryption Key.

Telephone call #

Use this term when referring to the user making a telephone type call, where the user holds the radio similar to that when holding a telephone handset or mobile phone.

Template #
  1. Something that serves as a model for others to copy.
  2. A set of customisation parameters and their assigned values defined with Radio Manager for configuring a radio.
Temporary/permanent disabling #

The process by which the network disables terminals which have been reported as lost or stolen or have fallen into unauthorised hands.

Terminal #

Also radio terminal or a mobile radio terminal or a TETRA mobile station (MS). A handheld, mobile or fixed radio unit connected to the TETRA system via air interface.

Terrestrial Trunked Radio (TETRA) #

The TETRA network is A radio system standard devised by ETSI now used globally by professional mobile radio users requiring a secure radio network.

TETRA uses Time Division Multiple Access (TDMA) with four channels on one 25kHz radio carrier. In addition to voice and dispatch services, the TETRA system supports several types of data communication including status messages and short data services (SDS) are provided over the system's control channel while packet-switched data or circuit-switched data communication uses specifically assigned channels.

The common mode of operation is in a group calling mode in which a single button is pressed to connect the user to other users in a selected call group and/or a dispatcher. The ETSI standard for digital trunked radio communications (earlier known as Trans-European Trunked Radio and before that MDTRS Mobile Digital Trunked Radio System).

TETRA Equipment Identity (TEI) #

Fixed number hard coded into a TETRA radio to give it a unique identifier.

TETRA MoU Association #

The TETRA MoU Association founded in 1994 to support promotion of ETSI TETRA standard worldwide, now known as the TETRA and Critical Communications Association.

TETRA Interoperability Profile (TIP) #

A test specification produced under the TETRA Association for testing TETRA equipment from different suppliers.


TETRA Voice + Data, the suite of TETRA standards normally referred to as 'TETRA'.


Telecommunications Industry Association, a U.S. standardisation body.

Time Division Multiple Access #

Technology for delivering digital wireless service that works by dividing a radio frequency into time slots and then allocating slots to multiple calls. In this way, a single frequency can support multiple, simultaneous, communication channels.


Top level screen. The top level of a menu driven GUI.

TNP 1 #

TETRA Network Protocol 1.

Traffic Encryption Key (TEK) #

End to end keys used to protect the user traffic payload.

Transmit Inhibit #

An operational mode for use in RF sensitive areas, that allows the radio to continue operating without transmitting. When Transmit Inhibit is activated and deactivated, a status message is sent confirming the operational state of the terminal.

Trunked Mode Operation #

Radios operating over the TETRA network.

Trunked radio communications #

A computer controlled communications system, which allocates communication channel for a call (either voice or data) from a "common pool" of available channels, and at the end of that call, returns them to the same "pool" to be reallocated for another call.

TS #

Time slot.

Twist-and-Zoom #

Sepura radios can be programmed so that when you turn the radio through ±90 degrees from the normal vertical position, images automatically maximise to use the full screen area.



User Datagram Protocol.


User Defined Scan List.

UL #

Uplink. RF Connection between a radio terminal and a base station.

Ultra-High Frequency #

Denotes a frequency range of electromagnetic waves between 300 MHz and 3,000 MHz (3 GHz). As UHF frequencies use a shorter wavelength they are generally used when working in and around buildings as the communication waves penetrate walls and steel structures best. The UHF frequency band has more available channels, so in more populated areas UHF is less likely to have interference from other two way radios.

Up Navigation Key #

The Up navigation key is one of the keys on a Sepura radio which allows you to select options on the display.

User Defined Scan List #

Pre-programmed (optionally user editable) list of scanned groups.

User profile #

User profiles are pre-set combinations of alerts and settings on a Sepura radio designed to match the user's circumstances or environment. If the User Profiles feature has been customised it allows you to switch easily between user profiles. When a user profile is selected, an icon is displayed on the status line at the top right of the display to indicate which user profile is active.


V+D #

Voice plus Data.

Virtual Console #

Sepura's Virtual Console provides control of a Sepura TETRA mobile or gateway from a Windows-based or in-vehicle mobile data radio. The Virtual Console can be customised and integrated into other applications as an active X control. It can also be connected remotely via an IP connection providing access to remote radios or radio access in an office environment.

Very High Frequency (VHF) #

A range of radio frequency electromagnetic waves from 30 MHz to 300 MHz, with corresponding wavelengths of ten to one metres. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF). Common uses for VHF are FM radio broadcasting, television broadcasting, land mobile stations (emergency, business, private use and military), long range data communication up to several tens of kilometres with radio modems, amateur radio, and marine communications.

Very large mode #

A selectable mode of operation on some Sepura radios that increases the size of the displayed information on the user interface. Because of the increased size of the information, only the talkgroup number or talkgroup name in the fast access box appears, together with the standard icons normally displayed on the Home screen.

Voice enunciation #

A feature on ‘black box’ radios that allows the user to hear which channels they are switching between instead of having to look down at the radio or feel the notches.

Volume control #

The control of the audio output from a device. The controlling of the volume is usually performed by either pressing a button, or in the case of Sepura radios the volume is controlled by the Navi-knob.


Whisper mode #

A customisable feature on a Sepura radio which adjusts the sensitivity of the microphone to allow the user to whisper verbal communications during covert operations.

Welcome screen #

A screen that is displayed when the user accesses the GUI for the first time. The screen is configurable with some users choosing to display a company logo on the screen.

Wireless Application Protocol (WAP) #

A protocol used to transfer data such as web pages over a computer network to cellular phones and other handheld wireless devices. open protocol for delivery of Internet content over radio path in a condensed format.

Find your nearest partner to buy

How To Buy