Hi everyone, I have a new pair of Tenda PH6 gigabit homeplugs talking to each other perfectly. I now want to add a single older generic branded 10-year old homeplugAV 200mbps adapter to the network as this is connected to my NVR up in the attic. However when I try simply plugging it in and switch it on, one of the new Tenda adapters reports a red light on the PLC LED almost immediately. Remove it from the wall, the Tenda shows 3 greens and is happy as Larry. Can somebody tell me how to get all 3 adapters talking to each other nicely? I have a 4th 200mbps if this would help but my understanding was that HomeplugAV and AV2 are inter-operable and it's a matter of plug and play? Any help would be appreciated thanks!