The ZyXel PLA4205 HD power line adapter is the fastest I've seen yet, thanks to the combination of the Powerline AV 500 standard and Gigabit Ethernet.
It offers more than twice the speed of a regular Ethernet connection, which is all the more reason you should get a pair of these instead of running network cable to that far corner of the house where your Wi-Fi signal can't reach.
The PLA4205 isn't perfect since it doesn't come with a pass-through power socket. The adapter itself could also stand to slim down a bit to keep the wall socket area clear, or use power cable to connect to the wall, instead of the current snap-on design.
At the street price of around $50 per unit or around $80 for a kit of two, however, the ZyXel PLA4205 is one of the best deals for those wanting to build or expand a power line home network. Not only does it save you setup time, it also offers speed closer to that of a Gigabit Ethernet network than any of its peers. See our list of top power line adapter options.
Design and features
The ZyXel PLA4205 is quite large, about twice the size of the recently reviewed Actiontec PWR500. On the bottom, toward one of its sides, it has a two-prong power connector that goes into a wall socket. This snap-on design is convenient but also means that the adapter will obstruct access to any adjacent receptacles. And since the adapter doesn't comes with a pass-through power socket, you shouldn't use it in a place where there's only one wall socket.
On the far side from the two prongs, the PLA4205 has a Gigabit Ethernet (1,000Mbps) port. This is an important difference from the Actiontec PWR500, which has only a regular Ethernet 100Mbps port. This means the PLA4205 can offer the real benefit of the Powerline AV 500 standard it supports, which caps at 500Mbps. The Actiontec PWR500 also theoretically supports Powerline AV 500, but because of the speed at which its port caps, that of the regular Ethernet standard, which is only 100Mbps.
On top of the ZyXel PLA4205 are an Encrypt button and a recessed Reset button. Pressing the Encrypt button of multiple units within a two-minute period will create a secure power line network in between them. This is a helpful feature in case you live in an apartment building and don't want neighbors to tap in to your home network by using an adapter. This is quite a real risk since the ZyXel PLA4205 is compatible with basically all power line adapters on the market. The Reset button restores the adapter to its default settings, in which no security feature is used.