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Mobile Terminals

The SRG3900 is the world’s most successful TETRA Gateway.

Its extensive range of control console solutions, audio accessories and install options means it can be found in the world’s police, fire and ambulance vehicles; in motorcycles, trains, mining vehicles, helicopters, patrol boats and exposed rigid inflatable boats, as well as, in mobile control/incident response vehicles and in emergency control rooms.

With a class-leading 10 Watts of RF power, and the most proven gateway and repeater technology on the market, the SRG3900 TETRA mobile extends communication into areas otherwise beyond network coverage.


DMO Gateway DMO Gateway

The SRG3900 pioneered DMO-Gateway and is the world’s most widely deployed TETRA range extension solution. The SRG3900 is used to bridge TMO with DMO coverage in blind spots such as buildings and tunnels


Use as a DMO-Repeater to increase DMO coverage. The SRG3900 is used to bridge two DMO radio users

Secure Secure

Designed for mission critical use, the SRG3900 supports ETSI and SFPG recommended Air Interface Encryption and End to End Encryption

Wide range of accessories Wide range of accessories

Wide range of accessories for audio, power, control and installation

Sunlight visible display Sunlight visible display

Dual illumination technology ensures clarity under all light conditions (with Sepura Colour Consoles)

Advanced Safety Features Advanced Safety Features

Protection and reassurance for lone or remote workers


Highly sensitive GNSS positioning, including compatibility with GPS and Glonass

Clear audio Clear audio

Advanced noise processing and a large loudspeaker deliver outstanding audio, even in loud environments.

The full SRG3900 technical specifications are available for download at the bottom of this page.

SRG3900 Specification


177 X 50 X 110 mm


980 g


10.8 V to 15.6 V, DC

RF Power

Class 2

Frequency Bands

344-400 MHz, 380-430 MHz, 407-473 MHz, 806-870 MHz

Static Receiver Sensitivity

-112 dBm

Dynamic Receiver Sensitivity

-103 dBm

Speaker Audio

8 W (rated audio output)

Operating Temperature

-30°C to +70°C

Storage Temperature

-40°C to +85°C

IP Rating



See console products (SCC3, HBC3)

Secondary Data Bearer




Side Soft keys


Water Porting



GPS, Glonass

Accessories compatible with SRG3900








  • In locations where normal TMO network coverage is unavailable or unreliable, users can switch their radios to Direct mode to maintain communication.

    To increase the distance between two Direct mode users, place a Sepura radio operating as a DMO-Repeater in between. Calls made from one DMO radio via the DMO-Repeater will be rebroadcast to other DMO users.

    Key Features

    • Voice calls (Encrypted and Clear)
    • Status and SDS message
    • Emergency calls
    • Call Participation and Call Monitoring


    • Type-1A-DMO-Repeater for efficient spectrum use

    Ordering Part Numbers

    • SC20, SC21 and SCG22 Series: 600-00261
    • STP9000, STP8X Series: 600-00004
    • SRG3900 Series: 600-00005

    A DMO-Gateway creates a communication link between TMO network users and DMO users. The DMO-Gateway re-transmits data received between the two types of users.

    DMO-Gateway can be used by users who cannot connect to the TMO network, perhaps because they are in a network blind spot such as a tunnel, or within a building. A DMO-Gateway placed within the TMO coverage enables the extension of network coverage in such blind spots, connecting the DMO users to the network.

    Key Features

    • Voice and Data
    • Intelligent call conversion
    • Safer operations

    Ordering Part Numbers

    • SRG3900 Series: 600-00006
    • SCG Gateway Software: 600-00896
    • SCG Gateway and Repeater Software: 600-00897

    The Sepura Virtual Console (VC) is a software package that allows control of an SRG3900 radio from a Windows based terminal, saving valuable dashboard space in today’s congested public safety vehicles. The VC is designed as a Windows™ ActiveX Control which allows easy integration into 3rd party applications and containers that will accept ActiveX Objects such as HTML/XML pages.

    Ordering Part Numbers

    • SRG Single Virtual Console: 600-00026
    • SRG Second Virtual Console: 600-00027

    A fixed level audio output is provided in the SRG3900 mobile radio. This is available on Interface 2 and is independent of the output audio level on Interface 1 and the loudspeaker connected to the mobile transceiver.

    Mobile radios can support audio input on one or both of the console interface connectors without a physical Console or Audio Interface Unit (AIU) being present. This allows installation of 3rd party control heads operating the radio with control of audio accessories bringing saving in investment and maintenance.

    Ordering Part Number

    • SRG3900 and SCG22 Audio Line In & Line Out: 600-00033

    Soft key functions are a collection of special radio features that can be triggered with a single long key press. It provides quick and easy access to often used radio features.

    This feature enables a Hayes AT command to trigger specific radio functions via the PEI port.

    Please contact Sepura Customer Support or your local Sales representative for a list of features available for each radio platform.

    Ordering Part Numbers

    • STP, SRG , SRH and SRC: 600-00037
    • SC20, SC21 and SCG22: 600-00275

    Callout provides a user friendly interface to distribute critical information quickly and efficiently to a larger number of users.

    In the event of an incident, the feature draws the radio users attention forcing a response. Optional phases allow specific groups to be attached for subsequent exchange of information.

    The Feature Includes

    • Simple Callout
    • Full Callout

    Ordering Part Numbers

    • STP/SRH/SRG Series: 600-00073
    • SC20, SC21 and SCG22: 600-00269

    Enables rapid, simultaneous distribution of images and associated text to whole groups of users rapidly and efficiently, key examples include enabling quick apprehension of wanted persons or swift identification of missing children.

    Distribution of the same picture using Packet Data would have required dedicated network resource for each recipient.

    Messages can also be sent securely using E2EE.

    Key Features

    • 'Slices' the images and sends via SDS
    • Images sent simultaneously to hundreds of users
    • Does not require Packet data session
    • Messages can be sent securely using E2EE

    Ordering Part Numbers

    • STP, SRG and SRH Series: 600-00102
    • SC20, SC21 and SCG22: 600-00271

    A Short Data Application (SDA) enables a Sepura terminal user to send and receive information in a user friendly form based environment. This makes sending and receipt of SDS message an effortless task by presenting the user with information in a form that is simple and easy to read. Typically, an SDA will help the end user with an existing work flow process by improving user experience and making efficient use of time.

    Features in this pack follow on from the SDS Templates functionality released in V5.0, enhancing it by providing the ability for end users to define their own templates, supporting user defined protocols and applications.

    Ordering Part Numbers

    • STP, SRG and SRH Series: 600-00103
    • SC20, SC21 and SCG22: 600-00275

    Radios are normally configured to route messages and voice to pre-configured destinations. With this feature, radios can be further configured to route status messages, position reports and emergency voice to a destination other than the pre-configured defaults. The alternative destinations are determined at run time based upon the Selected talkgroup. Change of Selected talkgroup automatically changes the destination address for the following functions;

    • Quick Status Destinations triggered via softkeys
    • Default Status Destination triggered via menu and/or the Mode Key
    • Primary Position Destination
    • Secondary Position Destination
    • Emergency Status Destination
    • Emergency Voice Destination

    Ordering Part Number

    • SC20, SC21, SCG22 STP and SRG Series: 600-00347

    In trunk mode, talkgroups are identified by their MNI and GSSI. On selection of a talkgroup, this feature enables the radio to automatically select the TETRA network based on the talkgroup’s MNI. Press of a single key changes the network and selects the talkgroup.

    Ordering Part Number

    • SC20, SC21, SCG22 STP and SRG Series: 600-00348

    A radio User can navigate through the configured list of TMO and DMO to select the required talkgroup. This feature additionally triggers an automatic selection of the operating mode; Trunk or Direct, depending upon the selected talkgroup.

    Ordering Part Number

    • SC20, SC21, SCG22, STP and SRG Series: 600-00349

    Radios support a number of features that can be configured to suit a user’s operational requirement. Some radio settings e.g. backlight resolution, alert level, active speaker etc. can be further adjusted during run time. This feature resets the radio back to the default configuration eliminating personal preferences.

    An option to preserve Phonebook, talkgroup and message boxes is available. If enabled, the reset option retains these data.

    Reset option can be activated from from the menu syetem, softkey, over the air and when integrated into an SDA.

    Ordering Part Number

    • SC20, SC21. SCG22 STP and SRG Series: 600-00350

    Radios can be configured with a list of up to 150 Location Areas (LA). The radio prefers these LAs when acquiring a cell at switch on or during re-selection. However, if the coverage gets weaker or non-existent the radio will register on an LA outside this list. Registering a similar group of users on the same LA ensures efficient use of TETRA resource.

    Additionally, the radio can be forced to only use cells from the the configured LA list. Even if the coverage on these LAs drops, the radio will not acquire an LA outside of the LA list.

    Ordering Part Number

    • SC20, SC21, SCG22, STP and SRG Series: 600-00351

    The top level screen of the radio enables a dynamic display.

    The display includes:

    • Radio Status Area
    • Information Area consisting of 4 or 6 lines
    • Shortcut and Notification Bar

    The radio status area comprises elements of variable radio status icons, permanent status icons, and radio status text, depending on the radio.

    The screen can be configured to include an Information Area. Using the Radio Manager, users can add or remove an information line and define how it is displayed. The information line includes display of talkgroup and folder, time, date and PTT mode. These can be formatted with a choice of colour and style for greater visual impact.

    The Shortcut Bar provides means to configure and access commonly used radio features (Shortcuts). It also provides visual status of the radio features (Notifications) on the top level screen. Selecting an icon triggers a radio action relevant to the icon e.g. opens an unread message or alerts the user when the radio is placed in Transmit Inhibit state.

    Ordering Part Numbers

    • STP, SCG22 and SRG series: 600-00352
    • SC2 series: Included as standard

    The transmit power of a radio operating in DMO, DMO-Repeater & DMO-Gateway mode can be set from the MMI. Users are offered an onscreen choice, dependent on the radio's hardware capability, allowing it to be set to the user's choice.

    On selection, an icon indicates whether the chosen power is higher or lower than the default setting. The radios revert to default power setting on a restart. The display text can be configured from the Radio Manager to user’s choice e.g. High Power and Low Power.

    Ordering Part Number

    • SC20. SC21 SCG22, STP, SRG Series: 600-00353

    AIM is the TETRA air interface mechanism by which a radio obtains service on a network (visited) other than its own Home Network, i.e. a network with a Mobile Network Identity (MNI) different from that of its Home Network. The use case is the TETRA radio users who may roam into another network, normally another country, for operational use e.g. a fire crew attending an emergency on the other side of the border due to its quicker accessibility.

    Ordering Part Number

    • SC20, SC21, SCG22, STP and SRG Series: 600-00354

    E2EE offers an additional and independent level of security to AIE. Encrypted data can only be decrypted by the correct combination of the algorithm and traffic key used by the transmitting party to encrypt the data. This avoids a man-in-the-middle attack as the crypto material is only available with the transmitting and receiving parties.

    The following options for E2EE are available

    • Embedded E2EE (without tamper protection)
    • ESM Protected E2EE (with tamper protection)
      • In-Country (Private, Local) E2EE algorithm
      • Multiple E2EE algorithms
    • Smart Card E2EE

    Please contact your account manager to discuss your requirements.

    This function allows a user working alone to indicate that they are safe. The radio periodically emits an alert tone to which the user is required to acknowledge by pressing one of the keys on the radio. Failure to do so triggers the radio to send an Emergency Status message to the control room.

    Ordering Part Numbers

    • STP and SRG: included as standard
    • SC20, SC21 and SCG22: 600-00267

    Packet Data provides a mechanism to transport IPv4 traffic e.g. images, files etc. over the TETRA bearer. This enables applications in a standardised IP environment the ability to use industry standard transport mechanisms such as UDP and TCP providing a framework to provide fast and flexible service. Packet Data services can only be accessed from the PEI port of the terminal.

    Feature enables Single slot and Multi slot packet data capability in the radio.

    Ordering Part Numbers

    • STP and SRG: incuded as standard
    • SC20, SC21 and SCG22: 600-00271

    Wireless Application Protocol (WAP) is a standard for retrieving information over a mobile wireless network including TETRA. Internet has become part of our lives and WAP offers connectivity from small personal devices when we are on the go. It offers the user to check ones mail or make a flight-reservation online or query the national database system to identify a stolen car.

    Feature enables a WAP browser on the Sepura radio.

    Ordering Part Numbers

    • STP and SRG: included as standard
    • SC20, SC21 and SCG22: 600-00271

    Out of Coverage Position Report Buffer

    Sepura radios equipped with GNSS receivers determine the user’s position and then automatically inform the command centre of the radio’s position. Knowing the user’s position ensures whereabouts are known at all times and officer’s safety is ensured. Position reports also monitor a user’s movements ensuring time and resource is efficiently managed.

    The out of coverage reports can be used to analyse network black spots and piece together the user’s activity.

    Fake Switch Off

    The feature allows discreet tracking of switched off radios. With the feature enabled, the radio does not power off completely when the switch off button is pressed. The radio enters a fake switch off state where TETRA services are denied to the user and all display and alerts are disabled. To the user the radio appears to be switched off. However, the radio continues to send position reports allowing the radio to be tracked by authorised personnel.

    Ordering Part Number

    • SC20, SC21, SCG22, STP and SRG: 600-00373