Radio Bridge User Guide

Radio Bridge User Guide

The Voisus Radio Bridge performs two major functions:

  • Voice Rx/Tx: Connect real radios to your network and stream live, over-the-air traffic to and from Voisus operators and the DIS network.
  • Remote Control: Remotely control live radios over the network.

Voice Rx/Tx

ASTi's Voice Rx/Tx connects live and simulated training environments, distributing live, over-the-air voice traffic via data networks. It is officially supported for the following radio transceivers (RTs):

Description Model
Falcon II PRC-117
Multiband Inter/Intra Team Radio (MBITR), JTRS Enhanced MBITR (JEM) PRC-148
Falcon III PRC-152
LOS Transceiver URC-200

Other radio types are supported by manually configuring In Gain, In Threshold, Out Gain, and Rx Delay. ASTi recommends that manual configurations are done with ASTi support to ensure optimal performance.


  • Radio Re-Transmission

    Extend live radio communications among distant sites through data networks.

  • Radio Interoperability

    Bridge incompatible radio systems and join multiple radio nets into conferences.

  • Flexibility

    Combine a wide variety of live and simulated radios.

System Architecture

Live base radios connect to ACE-RIUs or AI-S devices, linking the live radios to the simulated training environment over the network.

How Voice Rx/Tx Works


The live radio audio is digitized and sent through a software gate. The gate (or noise gate) controls the volume of the live radio signal by silencing the signal below a certain threshold value. This value is chosen such that when the live radio is idle the radio audio will fall below the threshold, and when it is actively receiving the audio will rise above the threshold. This way, the gate output will only be active when the live radio is actively receiving.

The gate output audio is then sent to a virtual radio, effectively relaying the live radio audio. When the live radio is actively receiving, the virtual radio will be actively transmitting and relaying the live radio audio.


When the virtual radio starts receiving a trasmission from another virtual radio, it sends the receive audio to the live radio. Along with the audio, a discrete signal is sent to activate the live radio's PTT. This way the live radio starts actively transmitting the audio received by the virtual radio.

Transitioning between Live-to-Virtual and Virtual-to-Live

Transitions between transmit states occur after a period of measured inactivity. If a live radio is sensed as actively receiving, it must cease receiving before it can transmit. Likewise, if a virtual radio is actively receiving, it must cease receiving before it can transmit.


Step 1: Live Radio Installation

Follow the steps below to install and configure the live base radios and live field radios. The live base radios are the radios that are connected to audio distribution devices (ACE-RIUs and AI-S devices). The live field radios are the remote radios out in the field.

  1. Configure Base Radio Settings

    Configure the following settings on the live base radio.

    Radio Volume Mic Gain Squelch Model COMSEC
    SINCGARS RT-1523C/D Max (Full CW) Whisper = OFF ON SC or FH PT or CT
    SINCGARS RT-1523E/F 9 Whisper = OFF ON SC or FH PT or CT
    PRC-117 9 N/A ON SC or FH PT or CT
    PRC-148* 4 Mic Lvl = High ON SC or FH PT or CT
    PRC-152 9 N/A ON SC or FH PT or CT
    URC-200 Max (Full CW) N/A ON SC or FH PT or CT

    *Additional configuration for the PRC-148:

    • MODE / Audio Path = TOP AUDIO. Disconnect the PRC-148 from the ACE-RIU before switching the Audio Path to TOP AUDIO. "Hot switching" the radio's audio path may cause the ACE-RIU to go offline, requiring system reboot.
  2. Connect Base Radio to ACE-RIU or AI-S Device

    Connect the base radio's handset connection point to an ACE-RIU* or AI-S device with the appropriate cable:

    Device ASTi cable
    ACE-RIU CA-D9M-NC6M-25-C
    AI-S CA-D15M-NC6M-25-C

    Ensure that the ACE-RIU or AI-S device is connected to the Voisus server.

    *The ACE-RIU connected to the live radio must be labeled "ACE-RIU Radio", indicating that its jumper settings are configured to interface with live radios. For more details, reference the ACE-RIU Technical User Guide Appendix A: ACE-RIU Configuration for Radio Bridge and Remote Control.

  3. Configure SC Frequencies and FH Net Settings

    Configure unique SC frequencies or FH net settings for each base radio. These settings must be unique to ensure proper system performance.


    If MODE-FH or COMSEC-CT settings are selected on any of the radio nets, follow the proper procedures for loading the FH Data or COMSEC Keys into the base and field radios. Refer to the radio's manual for fill procedure details.

  5. Set Transmit Power

    Ideally, the base radio should be installed so that a high fidelity radio link with field radios is established using LOW transmit power on the base radio. OE-254 (tower) antennas are highly recommended for increasing ranges, improving RF link fidelity and greatly reducing the chance of RFI.

    The base radio may be set to MEDIUM transmit power, but the possibility of Radio Frequency Interference (RFI) between the base radio and the ASTi system is increased. If system malfunctions occur (such as spurious transmissions or increased audio noise), re-establish the base radio to field radio links using LOW power.

    Base radios should not use HIGH transmit power. RFI will occur between the base radios and the ASTi system.

  6. Configure Field Radios

    Configure the nets on field radios with MODE and COMSEC panel settings that match the corresponding nets on the base radios.

  7. Perform Standard Radio Check

    The final step in the live radio installation procedure is to perform a standard radio check between each set of base and field radios as part of the system operational checkout.

Step 2: Configure Hardware

  1. Using the Voisus web interface, open the Hardware Devices page.

  2. Locate the ACE-RIU or AI-S device that the base radio is connected to. Devices are listed by MAC address.

  3. Audio distribution devices (ACE-RIUs, ACU2s, and AI-S devices) must be added to the cloud before they can be utilized.

    To assign a specific device to your cloud, use the checkbox to select the device, then press the button.

  4. Create a unique Channel Identifier for each channel connected to a base radio.

Step 3: Scenario Management

  1. Create a new Scenario. If desired, use the RadioBridge4 or RadioBridge8 example scenario, which are preconfigured with virtual nets in the Comm Plan.

  2. Run the Scenario and open it.

Step 4: Comm Plan

If necessary, edit the net names, frequencies, waveforms, and other parameters to match the virtual radio nets that the live radios will bridge to.

Step 5: DIS Settings

Configure the DIS Settings for your specific exercise.

Step 6: Voice Rx/Tx

On the Voice Rx/Tx page you will map the live radio's Channel Identifier to a Virtual Net.

Add a Live Radio

  1. Click the "+" button to add a new live radio.
  2. Click the radio name to edit it.
  3. Use the drop-down menu to select the Channel Identifier associated with the live radio. Channel Identifiers are named on the Hardware Devices page.
  4. Select a Virtual Net for communication between the live radio and virtual radios.
  5. The live radio will now be able to communicate with simulated radios over the virtual net.

Advanced Configuration

The Show Options button displays advanced settings that can be used to fine-tune the audio characteristics of the live radio interface. In most cases, with a standard, supported live radio, these parameters should not need to be modified.

  • Presets: If changes are made to the settings, use the "Save As..." button to save them for future use. The "Load..." button loads presets saved to your server.

  • Settings: Fine-tune the audio characteristics of the live radio interface.

    • In Gain: A gain multiplier applied to live radio receive audio. This gain is applied before the audio gets to the detection logic (see In Threshold, below). A larger value results in network operators receiving live radio audio at a higher level.

    • In Threshold: A value in dB used as a threshold for detecting receive audio from the live radio.

    • Out Gain: A gain multiplier applied to live radio transmit audio. A larger value results in live radio operators (for example, in the field) receiving transmissions from network operators at a higher level.

    • Rx Delay: A delay value in seconds used to prevent spurious live radio re-transmissions ("chatter") that can occur with certain radio types. This is sometimes referred to as "hang time" or "drop out delay". In most cases, this value does not need to be adjusted.

  • Status: View Rx/Tx status for live-to-virtual communications.

Remote Control

ASTi's Remote Radio Control has the ability to control live radio assets remotely through the Voisus web interface and the Voisus Client for Desktops and Tablets. Live radios can be located in the same room or in a facility miles away. Radio configuration is performed quickly and conveniently over the network from any computer with a suitable web browser. Changes can be made on the fly without interruption to training and while monitoring the radio state to ensure that radios are operating properly and in the correct configuration.


Remote Radio Control is currently available for the following radios:

  • URC-200
  • PRC-117F
  • PRC-117G
  • PRC-152

Contact ASTi to inquire about other live radios.


The following equipment is needed for Remote Radio Control:


Note: The PRC-152 radio's remote control feature is only compatible with the AI-S device.

Radio Control Kit

ASTi sells a radio control kit for each supported radio, which includes the following:

  • Serial Data Cable: connects the live radio to the Serial Data Converter.
  • Serial Data Converter: a compact module that converts serial data protocol from RS-232 to RS-422. It is powered through the serial data line.
  • Modular Data Cable: connects the Serial Data Converter to the ACE-RIU and AI-S serial data port.

Radio Control Kit Part Numbers

Live Radio ACE-RIU AI-S
URC-200 RCK-URC-200-01 RCK-URC-200-02
PRC-117F RCK-PRC-117F-01 RCK-PRC-117F-02
PRC-117G RCK-PRC-117G-01 RCK-PRC-117G-02
PRC-152 N/A RCK-PRC-152-02


If Remote Control qualifies as part of your solution (as ordered from ASTi), its setup documentation is included on the "ASTi Docs" CD that shipped with your system(s). If you cannot locate it, contact ASTi to receive a new CD, or individual documents at your request.