@Philbilly 

Based on the information available, Deco models that end with "Outdoor" (like your X20 Outdoor) support Power over Ethernet (PoE) as a power supply option. However, PoE is typically not the only power option • these outdoor models usually also come with standard power adapters.

Regarding your specific setup: your Deco X55 is a standard indoor model that does not have PoE capability, so it cannot provide power to other devices through the Ethernet cable. This means:

• You do NOT need a PoE injector if your X20 Outdoor came with a standard power adapter • you can simply use that adapter to power the unit while connecting it to your X55 via Ethernet cable for wired backhaul.

• You would only need a PoE injector if you specifically want to power the X20 Outdoor through the Ethernet cable (for example, if the installation location doesn't have easy access to a power outlet).