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KNX Gateways for Alarm Systems / JA-KNX User Manual

Troubleshooting

Diagnostic checks for alarm communication, gateway configuration and missing KNX data.

elausys · 18 September 2026
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In case of troubles to establish the communication, the JA-KNX gateway has a RX/TX LED that indicates the status of the RS485 communication. The LED blinks each time a telegram is sent or received by the gateway.

If the LED blinks but no telegram is received on the KNX side, verify that the ETS application program is loaded in the JA-KNX gateway and that group addresses are assigned to the required objects. Download the application program and read the firmware version of the JA-KNX module using the dedicated object. A string should be returned indicating the firmware version “JA-KNX Rx.xx”.

No alarm data

Verify 12 VDC, the RS485 connection, the JA-121T 9600-baud setting and that the alarm system is outside service mode. See Hardware and compatibility and Alarm system setup.

Frequently Asked Questions

What should I check when the alarm connection does not work?

Set the JA-121T to 9600 baud, connect the RS485 bus and provide 12 VDC to the interface. Exit alarm service mode before testing.

What should I check when alarm communication works but KNX data is missing?

Verify the KNX connection, the loaded ETS application and the group-address assignments. Read the Firmware object and test the required supported objects in ETS Group Monitor.

Keep exploring

Find the other guides for this product in the documentation.

Back to JA-KNX User Manual