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.
Note that the adapter's security feature works only with other power line devices from ZyXel. In an environment in which power line devices from different vendors are used, it's better to have the security feature turned off so the adapter can work with others.
There's nothing to setting up the ZyXel PLA4205. If you already use power line adapters at home, just plug the adapter into a wall socket, then connect it to a device such as a computer or a set-top box via a network cable, and you're done. If this is your first, you will need two adapters to create the first power line connection. In this case, using network cables, connect the first adapter to the router, then the second to a network device. After that just plug the two into their wall sockets and you're set. The network device is now part of your home network.
Note that, like all other powerline adapters, the ZyXel PLA4205 needs to be plugged directly into a wall socket, not a power surge protector or power strip, to work well.
The ZyXel PLA4205 offered stellar performance in my testing. For the testing, I used two PLA4205 units. One of them is connected to a Gigabit Ethernet router and the other to a computer with a Gigabit Ethernet network port. The connection consistently registered a sustained speed of 213Mbps, by far the fastest I've seen with power line adapters. For example, the second-fastest adapter is the
(Longer bars indicate better performance)
Note that power line networking's performance depends on the type and quality of the electrical wiring, so you might get a different experience at your place. Overall, I found the ZyXel PLA4205's performance to be the best I've seen. A power line network connection is very similar to a regular Ethernet connection that uses network cable. This means it's generally a lot stabler than a Wi-Fi connection, especially in terms of latency.
Despite the relatively bulky design and the lack of a pass-through socket, the ZyXel PLA4205 power line adapter is an excellent choice thanks to its stellar performance and ease of use.