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ZyXEL PLA5405 1200 Mbps Powerline Gigabit Ethernet Adapter Reviewed

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When it comes to powerline devices Im always curious to know how companies are allowed to market devices as being 1200Mb when they are not even theoretically able to get to that. Where I am from consumer laws do not allow false advertising and can open companies up to being sued. If I advertised a bottle of Coke as being 1ltr and only half filled it so there was only 500ml in the bottle Im sure a lot of people would be suing me :D

The UK Adverts Standard Authority recently banned a Zyxel 500Mbps powerline advert for advertising unrealistic and unachievable speeds, and also warned Zyxel about future claims:
http://www.asa.org.uk/Rulings/Adjud...cations-Corp/SHP_ADJ_278708.aspx#.VLeqpnulAal

What is likely to happen is just a small print disclaimer rather than any meaningful change to the currently (broken) system of advertising powerline products.
 
The 500/1200/1800 numbers are really a calculation of the maximum PHY rate that can be achieved by the chipset. This is also the case when you look at WiFi numbers. PHY rates are really the bits-per-symbol times symbols-per-second type of numbers.

Unfortunately there isn't a 1:1 correlation between PHY rates (data on the powerline or over-the-air) versus MAC rates (data on the Ethernet cables that you really care about). Its possible to achieve any PHY rate you want, however you might get a 100% error rate to achieve this PHY rate so the number ends up being meaningless. There is a perpetual struggle between engineering and marketing on these types of numbers - marketing teams want large numbers so that they can appear to be faster when you're looking at boxes on the store shelves, while engineers don't want to misrepresent anything. Marketing though usually wins these arguments.

Joe
 
Savy consumers can/should look at the very high numbers (PHY burst rates) and know "It's too good to be true".

But perhaps most don't know the jargon - even "Megabit" much less Mbps in context of IP, MAC, PHY layers.
 
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I bought the ZyXEL PLA5405 after reading the positive review here because I am having lots of problems with interference from neighboring WLANs in my home office.
I most sadly report that my experience with this kit was very disappointing. The kit works and has raised the throughput in my network from this particular location from 4MB/s (megabytes) to 7MB/s. The problem I have seen with these adapters is that they are very unstable. I can be reaching top speeds and suddenly drop to a miserable throughput of 2MB/s.
I have tested copying a 800MB file from one laptop to another that was connected all the time via ethernet to the router.
I am packing this kit and returning it immediately to the online store where I bought it from. Hopefully others will have a better experience than mine. This is an old house with old electrical cabling so your millage with this technology may be different.
I am now thinking on investing in a new wireless router that can maybe help me better than Homeplug in my situation.
 

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