Power-line networking lets you take advantage of a preexisting home network--your electrical system--to transmit data between networked devices. Each electrical outlet serves as a node on the network and any device, such as a digital media adapter or a PC, that's connected to the electrical system via an adapter is part of the LAN. Zyxel's previous iteration of the product, the PL-100, is based on the HomePlug 1 spec. The PLA-400 device is based on the new spec--HomePlug AV--which specifically address the need for QoS for latency-sensitive services such as HDTV and VoIP (HomePlug AV is backward-compatible with HomePlug 1). The theoretic throughput of HomePlug AV products is 200Mbps, but real-world performance is pegged at around 100Mbps.
The Zyxel PLA-400 uses the same design as its predecessor, the PL-100. The compact silver-and-black brick houses four LED indicator lights on the front and a power port and an Ethernet port on the back. The bottom of the adapter has two holes for wall-mounting the device.
Setting up the PLA-400 is as simple as can be. To start, you'll need at least two adapters: one for your router and another for whatever device you're networking. In our case, it was simply a laptop computer. Connect the first adapter to one of your router's LAN ports and plug it in. Connect the second adapter to your device of choice via Ethernet cable and plug that one in to an outlet as well, and voila, you have a power-line network. Zyxel includes a configuration utility on CD, but you don't need it to get started. However, you will need to install it if you want to change the default password or monitor the other devices on your system. Because all the adapters on a network must use the same password to communicate, all PLA-400 adapters come with the same default password. For security reasons, however, it's recommended that you change it. (In some apartment buildings, for example, it's possible for multiple units to share an electrical system. Anyone on the same electrical system could plug in an adapter from the same maker and access your network if they know your password.) For security during transmission, the PLA-400 uses 128-bit AES encryption. Zyxel's site shows that the PLA-400 can currently support up to 16 total devices on the network, but a future firmware upgrade will allow it to support a whopping 64 devices, so fear not if you have multiple networkable gaming consoles, computers, VoIP phones, and printers or NAS drives.
Though Zyxel advertises the PLA-400's theoretical maximum throughput as 200Mbps, our Labs' test showed actual throughput to be much lower: an average of 35.56Mbps. This is an improvement over the PL-100's throughput but still behind the 52.7Mbps posted by the Netgear HD Powerline Ethernet Adapter. Still, 35.56Mbps is more than enough throughput to stream HD content to your home entertainment system.
Zyxel supports the PLA-400 with a limited two-year warranty. Phone support is available weekdays from 8 a.m. to 5 p.m. PT, and Zyxel has improved upon its previous support line by offering a toll-free phone number. You can also fill out a form on Zyxel's Web site to request assistance from tech support.