Powerline networking transfers data over powerlines, such as your homes internal power wiring. It uses two powerline adapters.
At one end, you plug a powerline adapter into a power socket, then attach an Ethernet cable between the power socket and a router. At the other end, you attach a powerline adapter to your ethernet enabled gadget (TV, laptops, etc) and the power socket.
Most powerline networking kits we see are single-port models, designed to extend your network to single PCs at locations that wireless won’t reliably reach.
The WD Livewire kit is different, offering four ports at each end of the connection, massively boosting the number of devices that can be attached to your network.
A side benefit is that you can boost the speed of your powerline network by hooking performance-sensitive components straight into the Livewire block, rather than having a router in the way.
Either way, performance is good: in our best-case test at close range the kit averaged 64.7Mbits/sec, while in our worst-case test at long range it returned a steady 46.2Mbits/sec.
At a reasonable price, these come highly recommended.