The KNX Line Coupler is a modular installation device that integrates the functions of a KNX line coupler and a KNX line repeater. When used as a line coupler, it connects the main line to the trunk or regional lines. As a line repeater, it allows more than 64 devices to be connected on a single bus line, providing electrical isolation in this way.

The coupler sends physical addresses, group addresses, and broadcast messages by route. When sending physical address messages by route, the coupler compares the target physical address with its own physical address. It automatically filters and determines whether to pass the corresponding physical address message. Messages are routed or not routed depending on parameter configuration. If the coupler does not receive the engineering-assigned physical address, it may cause the device to fail to communicate during commissioning.

The coupler provides a filtering table, where all group messages present in the filtering table are routed; otherwise, they are blocked, thereby reducing bus load. The filtering table is automatically generated by the ETS software tool according to the commissioning system. Configuring the filtering group addresses in the filtering table is very useful, especially during commissioning and diagnostics. Main group addresses in the range 0....13 can be configured for filtering and other parameters, while group messages with main group addresses 14....31 are not isolated.

If the coupler does not receive confirmation when routing messages or encounters transmission errors, it will repeat the messages up to 3 times. Parameters to prevent erroneous repeat group messages are set separately for the two lines. In the standard setting, this parameter can be set separately.

Generally, the coupler only acknowledges messages it routes. Parameter message confirmation parameters are set separately for the two lines.