Powerline networking, when it works, can be fantastic. Using the power lines in your home to send and receive network traffic is a fantastic way to avoid laying network cables through your house without having to resort to temperamental, and sometimes slow, wireless networks.

Devolo has been specialising in powerline networking devices for a while now, and its good reputation in this market is well earned. It's known for making high quality products that are easy to set up, reliable and – crucially – work.

The dLAN 200 AV USB Extender is a unique new product from Devolo that lets you plug a USB device straight into your dLAN powerline network. Any USB device you connect can then be accessed by any computer connected to the same network.

This can turn standard printers into network printers, and simple USB memory sticks into NAS backup devices for all your PCs. The technology has a lot of potential.

However, when we tested the dLAN 200 AV USB Extender in an existing powerline network with non-Devolo adaptors, the device wasn't found. Connecting the PC to a Devolo adaptor (included in the HomePlug AV Starter Kit) fixed the problem.

The USB device was found and installed as if it was plugged directly into the USB port. Unfortunately, transfer speeds were much slower, taking around two minutes to copy over 100MB of files, which would ordinarily take less than 30 seconds to complete.

The test environment had a lot of other devices plugged into sockets, and transfer speeds might be faster with a cleaner setup, but most homes will also have sockets in use.

Although transfer speeds might be on the slow side, on the whole it won't have a particularly noticeable impact on most tasks. Streaming movies from a connected USB hard drive was fine, for example.

It's a shame that if you already use another make of powerline adaptor, you'll have to get Devolo adaptors for each computer. While one comes with the Starter Kit, if you have to replace a number of adaptors, it could get expensive.

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