Application Note

Diagnosing Communications Issues Between Networked Training Devices (#115)

When diagnosing communications issues between networked training devices, the conversation almost always starts with, "I can't hear the other radio." Customers usually begin focusing on their own radio as the source of the problem. Our experience at ASTi, however, has shown that the radio is often NOT the culprit.

We propose that you take a few steps back, and look at the big picture. We recommend you start troubleshooting at the network level, proceed to investigate general DIS settings, and then examine radio modeling settings. If none of these resolves the issue, look at the audio distribution hardware.

At the network level, review settings for the relevant devices in the exercise, such as IP addresses, subnet masks, and gateways. Confirm switch settings and routing information between these systems. Perform "ping" tests to ensure they can connect to each other. If the networking checks out, but communications aren't functional, use ASTi's system tools to ensure network packets are being sent or received. If the issue persists, check the DIS settings.

A common source of frustration (and broken comms) is a misconfigured DIS UDP port number. Verify that all systems are using the same UDP port for DIS networking. Also check to ensure that all systems are using the same DIS version. ASTi systems support DIS versions 4 through 7, but many others do not. Some support only DIS 7, and reject all other versions; confirm this value is consistent across all systems. Next, verify both radios are configured with the same DIS exercise number. They will not talk to each other if they're on different exercises. You can use the Radio Monitor tool in both the Telestra and Voisus products to help you verify these parameters.

If you find that networking and DIS settings aren't the source of the problem, it's time to look inside the radio environment. For simulated radios to communicate, their frequencies, modulations, bandwidth, crypto settings, etc. must match. Differences in any of these settings may have a jamming effect, or may enable only one-way comms. In Voisus, the Radio Monitor page offers a useful comparison feature to help identify radio mismatches. Select the two or three radios of interest in the Radio Monitor, and click the "Diff" button. A new window will display any parameters that do not match between the selected radios. You can then make the necessary adjustments to your model or scenario.

Finally, look at your hardware. Are your ASTi audio devices powered on and connected to the ASTi server according to our User Guides? Telestra's RMS and the Voisus web interface provide diagnostics pages you can use to verify that the server can see the remote device. Also check that all audio cables are connected securely to the proper audio channels. Lastly, confirm that the gain and microphone power settings are appropriate for the type of headset to be used.

If you still can't hear the other radio, then maybe it's time to check our support website or send us an email at