In my offcie I use 6 Decos. 2 units for every 3 floors. All of them are connected to network using ethernet cable. On every floor there is switch installed. And then those three switches are connected to DrayTek Router working as main office router.

Decos are working only in AP Mode. There is a problem when switch on certain floor is off. Naturally it has to be ON but when  some work with electricity is done on the certain floor power is off and switch is also off but Decos are ON because they are connected to UPS (switch is not connected to UPS)

In that case 2 Decos loose ethernet connection and they want to establish wifi connection to the network. Such case makes a problem because there is weeak signal between floors and Devos HANGS UP all my network. Even computer connected to LAN has got BIG LAGS. It looks like all network is DOWN, pings are very slow.

When switch is again power ON then Deco again connects to newtowrk via ethernet cable and then all network again works properly without lags.

My question is: IS it possible to force Deco to use ONLY ethernet cable connection to connect to network? Only cable. When switch is off then there is no cable connection to Deco and Deco do not have connection to network and DO NOT TRY to connect via Wifi to another Deco. Is it possible?

I want to loose network on certain floor due to switch power off but on the other floors there would be stable network. Actually it is not stable because Deco without ethernet cable want to establish wifi cinnection to another Deco and all network is really really slow, many pockets are lost, many computer over LAN not working properly.