Telegram Acknowledgement

Always

The coupler acknowledges every received group telegram. This setting is particularly useful during commissioning when filter tables are not updated after every change or when devices are commissioned using a separate configuration tool instead of the ETS project.

Only when forwarded

The coupler compares the group address with the filter table. The telegram is acknowledged only if it is forwarded according to the filter settings. This setting is recommended for normal operation because it reduces bus traffic.

Always

The coupler acknowledges every received physically addressed telegram without checking its destination address. This setting is particularly useful during commissioning or when a programming interface is temporarily connected to different KNX lines. Alternatively, the filter function can be disabled using the Pass IA button.

Only when forwarded

The coupler compares the destination address with its own physical address or, when operating as a Segment Coupler, with the list of devices in the subordinate line segment. The telegram is acknowledged only if it is forwarded. This setting is recommended for normal operation.

Always reject (NACK)

The coupler rejects all physically addressed telegrams and returns a NACK Confirm. Physically addressed telegrams cannot pass through the coupler, and the coupler itself can no longer be addressed physically from the superordinate side (application download is not possible). This setting increases protection against unauthorized access but may significantly complicate normal maintenance. Secure Commissioning should be used when this operating mode is selected.