You only need one HT-EM4 if you have a MoCA-capable broadband device. If your router does not support MoCA, you will need two MoCA devices, one for your router and one for the device that you want to connect to, a gaming console for example.
You only need one HT-EM4 if you have a MoCA-capable broadband device. If your router does not support MoCA, you will need two MoCA devices, one for your router and one for the device that you want to connect to, a gaming console for example.