Powerline extends the existing LAN. To do this, one adapter must be connected to the router via the LAN cable supplied. The second adapter is then plugged in at the location where you want to use another device connected with a LAN cable.
ADSL signals cannot be transmitted with it. The Powerline devices use network technology called Ethernet. But if a Powerline adapter is connected to the ADSL modem via a LAN cable, you can still use it to cover the desired function and expand the existing home network accordingly.