ZyXEL 500Mbps Gigabit Powerline Adapters

“500Mbps Gigabit”


Simple my friend. 500Mbps. There’s two of them. BAM.

lots of good reviews (4.0 out of 5.0) over at Amazon

It looks like Amazon has these, but you only get 1 adapter, as far as I can tell.

Pretty good reviews.


So, this woot deal looks pretty good.

I would so buy this if I wasn’t a broke college kid…

Yeah… I was thinking the same thing. 500Mbps is not Gigabit. Gigabit (1024 Megabits) is Gigabit.

Just FYI, these will work as long as you’re on the same circuit in your house. If you have multiple breaker boxes, dual circuits, etc they will not communicate.

I bought two pairs of the slower version from AMZN, the PLA-407. Strangely, they worked great across different circuits for 24 hours. Then stopped communicating completely. Now one set will talk although at very slow rate, and sometimes the connection drops.

I learned of the same circuit issue with ZyXEL tech support, but no one there could explain why it worked properly for one day and then stopped.

Stupid question. Do I need this if I can get ethernet from my file server (video stream source) to my AV Receiver (or other stream destination)? Thanks.

I recently got a pair of HomePlug AV compatible powerline adapters (Netgear). Used for a room with poor WiFi reception. The room was on different phase circuit so poor speeds of 20-40Mbps. I swapped the circuit breaker to adjacent position and speeds doubled. Very reliable connection.

They may have worked temporarily if you had a 220 appliance running at the same time (ie dryer). Depending on the wiring, that can bridge the two 110 circuits in some homes allowing the two adapters to work. This often happens with folks who have X10 home automation devices on different circuits as well.

Looks like this set is less expensive on Amazon with free prime (2 day) shipping and a 30 day no questions asked return policy. Am I wrong or is this no deal at all?

[MOD: Are you looking at the two adapter set? That’s $99 on Amazon.]

You are confused, and ZyXEL support isn’t any better. This is almost certainly the same problem that affects X-10, and the circuit is not the cause.

The signal is kept between the hot and neutral prongs of the ZyXEL. Thus any other device that needs to communicate needs an (RF) clean path to the same hot and neutral.

Circuit breakers do not interfere with this RF path. So they are not isolated to individual circuits.

Just about every house though, has more than one hot ‘pole’ coming in from the utility. In your breaker box, there is an A side, and a B side. Half of the (120v nema 5-15/20 outlets in your house should be on A pole, half on B pole.

Some houses (particularly outside of the US) and commercial buildings have a third hot pole, but that is beyond the scope of this post.

All houses have a neutral conductor that is electrically ‘in between’ the hot poles.

120v circuits connect to one of the hot poles, and the neutral pole.

So half of the circuits/outlets in your house will be on one hot, and half on the other hot. So long as you have both units on the same hot, (and your wiring is in good condition) these units will always connect to each other.

So. Why then did you observe it working one day and not working the next???

You probably had the units on different hots. But I just said that they’d never work if they were on different hots! How could they have worked for a while?

Well, I didn’t say they would never. I said they needed a path to each other’s hots, and they had separate hot poles.

You can’t just wire the two hot poles together. (Unless you have a death wish). So how might that signal be making it from one hot pole to another?

240v circuits connect to both hot poles, and may or may not use a neutral. You undoubtedly have some number of 240v outlets and large appliances around the house. Most 240v appliances have a couple interesting traits:

  1. They are only running some fraction of the time.
  2. They are “dumb” devices. Electric, not Electronic. This typically means they have a very simple path from one hot to another hot. like through one big fat heating coil in an oven, or a motor coil in your HVAC.

These big fat connections between two hots are great at bridging signals. And so when the appliance is running, both hot poles can “talk to each other”. But the appliance… is intermittent. So when you saw it work, your oven was running, AC on, or you were drying clothes. Then whatever it was stopped, and communications were lost.

So what can you do?

  1. Have some 240v appliance always on. This solves the problem for me because I operate a hardwired 240v UPS for my computers.
  2. Get a signal bridge that is compatible with whatever protocol you want to use (no idea what this product uses)
  3. Get an RF bridge that is protocol independent.
  4. Hack your own signal bridge with a single 600v ceramic capacitor. This is what I did before my UPS. I installed the capacitor on a two pole breaker, and stood back as I flipped it on. It worked like a charm even though it looks like its asking for trouble. It’s still installed in my mom’s house even though she has no idea what X-10 is. :-p The exact specs of the capacitor, I found on some newsgroup. YMMV. Wear personal protective equipment and have a fire extinguisher ready.
  5. Buy an extra pair. Plug the extra pair into outlets you KNOW are on alternate hot poles, and connect them with a crossover cable.

PRO-TIP: When you have two hot poles you have single phase power. When you have three you have three-phase power.

Now for MY question. Will these interfere with X-10 powerline communications? I emailed support@zyxel before I started writing this message. I suspect not, because these are super high frequency compared to X-10. But who the hell knows right? This RF stuff is complimicated.

For those commenting on ‘Gigabit’ in the title:

That’s what ZyXEL calls it.

Are you a wizard?!

Hmm…call me crazy, but with all these other comments I read…I still have no clue what this is for and therefore why to get this deal. Am I missing something great?

I’m pretty sure the point is that you’ll only get 500Mbps if you have Gigabit ethernet feeding into it.

Common sense to those who know the difference, but it only takes a few calls to CS before a company realizes they need to make the distinction…

Nope. I’m a neckbearded GNU+Linux system admin.


I live in a historic home which the US Army says can’t be modified to install ethernet boxes. I needed a network connection from the office (where the cable modem resides) to the living room (which is where the HTPC and Roku reside). So, I tried wireless but couldn’t get a reliable signal. Next step was to try a set of ZyXEL PLA4200 adapters, similar to these but one of the adapters is also a 4-port hub. BAM! Both the HTPC and Roku get a decent signal and we can watch the Internet stream by on our TV. Life is good!