Function: The coupler connects two KNX lines together and guarantees electrical isolation between these lines. The exact function of the device is defined by the address and the selected application.
Line coupler: Connection of a line and a main line with or without a filter function.
The coupler is physically assigned to the secondary line (here: line).
Backbone coupler: Connection of a main line and a backbone line with or without a filter function. The coupler is physically assigned to the secondary line (here: main line).
Amplifier: Preparation and repetition of telegrams on a line, no filter function. Subdivision of a line into max. 4 independent line segments = max. 3 line repeaters per line connected in parallel. A separate power supply including a choke is required for each line segment.