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Line Coupler, MDRC

Line Coupler, MDRC

Product code: 2CDG110171R0011
The ABB KNX Line Coupler LK/S 4.2 is used as a line or area coupler or as a repeater. It provides electrical isolation between main line and line.
Price (Excluding GST)


The line coupler is used in larger installations to connect ABB KNX lines or areas. The lines or areas are galvanically isolated from one another. Filter tables can be used to reduce the telegram traffic between lines or areas. Within a line, the LK/S 4.1 can also be used as a repeater. Connection to main and subline via bus connection terminals.

Different application programs are available with the LK/S 4.2 for ETS 3 and ETS 4. Some of the functions for the ETS 4 are not available in the applications for the ETS 3.

In ETS 3, there is a separate application for coupling and for repeating (Couple/1.x or Repeat/1.x), in ETS 4, there is a common application (Couple Repeat/2.x). All applications are upwards compatible, i.e.:

  • The old applications of LK/S 4.1 can be loaded in the LK/S 4.2 (ETS 3). This is particularly useful if in an existing project an LK/S 4.1 has to be replaced by an LK/S 4.2.
  • The applications Couple/1.x or Repeat/1.x can be loaded in the LK/S 4.2 via the ETS 3 or the ETS 4.
  • The new application Couple Repeat/2.x with extended functional range is only available for the ETS 4.

Technical Details


  • Rated Voltage: 21...31 V DC, via the bus
  • Power Consumption: Maximum 0.25 W
  • Current Consumption: Maximum 12 mA
  • KNX- subline (2 = Line): Via left bus connection terminal
  • KNX- subline (1 = Main line): Via right bus connection terminal



Technology KNX
Mounting DIN Rail
Input voltage KNX Bus (29VDC)
Mounting Width 2MW
EAN 40 16779 88167 8

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