Zyxel PLA4201 Powerline Ethernet Adapter

Zyxel PLA4201 Powerline Ethernet Adapter



  1. Ian
    Whilst WiFi is by far the most popular (and convenient) network in the home, there are some occasions where it isn’t possible to wirelessly connect to devices. Range problems, limited connectivity options or interference may mean that a wired network is a preferred solution. However, it’s not particularly easy to re-wire a house with network cable, so this is where the powerline adapter can really shine.

    The Zyxel PLA4201 is marketed as 500mpbs, which is a big leap in speed compared to some of the other devices seen in previous years… although there is only a 10/100mbps port attached to the adapter (we’ll discuss this oddity later on in the review). The unit is IEEE 1901 compliant, so you’ll be able to use this with any other compatible kit – although if you’re starting from scratch it would be worthwhile sticking to the same unit where possible.

    Specifications:

    • Compliant with IEEE 1901 with data transfer rate of up to 500 Mbps data rate
    • Compatible with HomePlug AV standard
    • Max. range up to 300 meters over power line
    • 128-bit AES encryption
    • One 10/100 Mbps RJ-45 connector with auto MDI/MDIX support
    • Dimensions (WxDxH): 50 x 60 x 70 mm
    • Weight: 72 g

    The Adapters:

    The Zyxel PLA4201 is a compact device with a single Ethernet port, so it should easily fit alongside other plugs on a row. There’s no power pass-through, so you’ll lose a potential outlet, but it appears to work fine on extension cables/gangways if you are using one to provide sockets.

    There are 3 status LEDs on the front of the unit (power, quality and activity) and a single reset/encrypt button. The AES-128 encryption means that you can use the adapters in a communal building with shared wiring as you can control which other devices can join a particular network by using this button – data transmitted over the powerline would be practically impossible to intercept without knowing the AES key.

    Zyxel PLA4201.jpg
    If you don’t use the adapters (i.e. the connected device is off) then they’ll automatically go into a standby mode and reduce their power consumption. The claimed figures are 4W during use and 0.5W during standby, so the running cost is minimal in comparison to the hardware it connects to.

    Setting up the adapters is very straight forward and doesn’t require the use of any software, just follow the quick setup guide that you get in the box and press the reset/encrypt button correctly to join your set of powerline adapters. It’s simple enough that you’ll be up and running within a few minutes and can then forget about re-configuring them unless you change your network topology. Once they are all paired, plug in your Ethernet cable and you should be up and running.

    Software:

    Zyxel does include some management software with their powerline devices, however it isn’t much use unless you want to update the network name or change priority for specific adapters. There is a tab in the software which prompts you to download updated firmware direct from the Zyxel website, however there doesn’t appear to be any release available. Unless you have a specific need, I would suggest that most users skip installing this software and configure them using the onboard button.

    ZyxelSoftware.jpg

    Testing:


    In this article, we’re using four PLA4201s with a maximum distance between the furthest adapters of ~10m (although internal wiring route could be double this). One is connected to a QNAP NAS, two connect PCs and the final adapter connects to a PS3. Before using powerline adapters, WiFi would provide an intermittent signal to the furthest PC and would make it impossible to play any form of online gaming.

    The wiring in the house is fairly new and electrical equipment was operating as normal during the test (TVs, washing machine, etc…). As the signal piggybacks onto the internal wiring there will be a huge variation in performance between different setups, but this review should give a good indication of how the device will perform in a typical house. We used Totusoft's LAN Speed Test 1.2 to measure file transfer performance across the network.

    An interesting point to note is that the transfer speeds didn’t vary too much throughout the house. When testing all of the powerline connections, the average file transfer speed was approximately 52.55 mbps (~6.5MB/s), which is much slower than the headline “500mbps” that users may assume is achievable. This is mainly because we’re already limited by the 100mbps network port on the adapter, but mainly because the 500mbps is a theoretical maximum derived from the IEEE 1901 specifications – which has no basis in realistic performance expectations. It is quite misleading for Zyxel to market these adapters in such a way (as it simply isn’t possible to achieve this speed in this implementation), but it appears to be common across many other powerline brands.

    Ping times varied from 3ms to 7ms from powerline to powerline devices, so there’s very little latency introduced. Online gaming, video streaming and reliable file transfers were all possible now, whereas the previous wireless network couldn’t manage any of these things.

    Conclusion:

    The Zyxel PLA4201’s are very reasonably priced and have proven over months of use to be very reliable. The performance will be nowhere near that of a CAT5 wired setup, but as an alternative to expensive cabling solutions or limited WiFi, it does the job well. For general internet, streaming and moderate file transfer tasks, these adapters work very well. The only caution would be to not expect anywhere near the 500mpbs headline rate that you may have thought you would be able to achieve. If you’re out of options but need a cost effective way of creating a network of a large distance, these are an effective and reliable method.​