@rrp For your information, all the TP-Link powerline adapters are compatible with each other. You can add the AV600 to the existing AV500 network, and you need pair the new one and existing adapter...

@wobble Hello, if you have the single TL-WPA4220, you can connect it to the main router with a long cable and plug it into the garden or near to it to boost wifi signal. If you have a TL-WPA4220KIT,...

@Miroslav-P Hello, you can repeat the procedures to configure the extender 2 like you did on the first one. You can give it a static IP address and connect it to the extender 1's wifi with the same...

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