Product Reviews

If your home isn't well suited to wireless networking, perhaps because it's too large or has particularly thick walls, powerline networking is an alternative. Unlike Devolo's Wireless extender (opposite) Zyxel's adaptors don't plug directly into power sockets. Instead, a small box houses the electronics, and each adaptor uses a standard two-pin power cable.

This makes them similar to Devolo's dLAN 200 AVdesk adaptors; they have a similar name because HomePlug AV is a standard. It means that both sets are capable, in theory, of 200Mbit/s, which is more than enough for AV use, and high-definition video in particular. In fact, working

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on the basis that HD video needs a bandwidth of around 20Mbit/s, you should be able to have ten different HD video streams playing through the PLA-400 simultaneously.

Like wireless networks, however, the actual speed of powerline adaptors is much lower than their headline figures. We tested the PLA-400s by transferring a 100MB file between two Windows XP-based PCs, connected by a router with Gigabit Ethernet ports. Disappointingly, no matter which power sockets we tried, we never saw more than 32Mbit/s. This is the same speed as Devolo's HomePlug AV devices, but significantly slower than the 59.4Mbit/s throughout we got from D-Link's DHP-301 (What's New, Shopper October 2007). At least it's enough for a single HD video stream.

Setting up the adaptors is easy. Once you've plugged them in they find each other and establish a connection, informing you of this by lighting their respective Link LEDs. A configuration utility included on CD enables you to choose your own encryption key to prevent any neighbours who use HomePlug kit being able to join your network.

The HomePlug AV PLA-400 isn't bad value, but D-Link's better-performing DHP-301 plugs are a better choice and they're around £10 cheaper, too.