@TP-Link 

Thank you for your reply

just to clarify

currently I am using operating mode: Access point

Main deco is connected to the ISP router,

you say I can add another deco unit and connect the ethernet port also to the ISP router, and it will get the "signal source" from ISP router

since when I am looking now in the app on second deco, it is saying signal source <Main deco name>, and I don't see option to switch it.

@Shay972 

I run Deco mesh in Access Point mode. My Main Deco is named "Living Room."

My Satellite Deco M5 when connected by WiFi:

Same Satellite Deco M5 when connected by Ethernet cable to ISP router:

This is what you should expect to see. As long as it says "Ethernet," you have Satellite Deco M5 using wired connection for communication with Main Deco and for network traffic.

@Alexandre. 

Nice, Thanks - I will check the cable to the ISP router

@Alexandre. 

Thanks, I currently have my Deco P9 connected as access point to the switch, the A/C connectivity didn´t work in my house, so the mesh is wifi and my office is far away, so I get typically some 80 MB versus the 200 MB the rest of the house enjoys. I am thinking about connecting via wire all the Decos to get true full bandwidht in all, reading this thread seems to be no issue by doing so.

Thanks again