Have you ever had your X10 system suddenly stop working or experience a drastic decrease in the system's reliability? What causes a well-functioning X10 system to go from great to turkey?
This is actually a very common call (and email) for us. Besides folks asking for help on three-ways, (installing wall switches, that is), the mysterious "X10 Blackout" is our next most common request for help. It's also sometimes difficult for us to explain the problem or the caller to accept the cause. It's a fairly easy problem to fix since the X10 system was recently working well. We only need to figure out what events triggered the modules to stop responding.
Plug-in, tune in, drop out
It's very rare that "something" happened by itself that caused the X10 system to start malfunctioning. While, it's true that things burn out, (or as I like to say "release their stored smoke"), electrical properties of a device don't change too much over the years. The refrigerator still draws about the same amount of power, the toaster still burns your toast, and the television's picture is still crummy on channel six. Minor changes do slowly occur to internal electrical components like capacitors and crystals, but for this problem, they won't affect X10 signals. Fluorescent light ballast and some motors will begin to generate electrical interference as they age, but this is a slow process. What were getting to is some event has caused this problem to occur almost instantly.
When many X10 modules stop responding suddenly, it usually due to something that was recently plugged into the homes electricity lines. When the Tech Support folks ask about this, the common response is:
"I haven't added anything to my house."
What people don't realize is that a new computer and monitor that replaced an old unit is a new device. The battery recharger for the electric toothbrush is a new device. Our favorite, the new TV they bought for the den six week ago. Eventually they fess up and admit that they or someone in their household has plugged something new into an electricity socket. The bottom line is that something, which was installed or plugged in recently, is possibly causing a problem with the X10 signals.
They're just everywhere!
How is it possible that a TV or computer, something that has nothing to do with X10 signals, possibly be causing interference? Since the X10 signal goes everywhere in your home, some devices will have more of an effect on the signal strength than other things. X10 signals are like water pressure in pipes, it actually goes everywhere it can. For the techies out there, the electrical impedance (at 121kHz) is low as compared to other devices thereby presenting a low resistance path to ground. Now back to our non-technical way of explaining things.
When people call about this problem, I have often used a plumbing analogy. If you called a plumber to your home because of low-water pressure and he suggested increasing the water pressure instead of fixing many small leaks, you would thank him for his time and hire another plumber! In the X10 world, electrical devices that are not even X10 related can cause these leaks. We know of many devices that will actually absorb X10 signals that are not intended for them. Just because there is no X10 receiver on a particular circuit doesn't mean that the signal doesn't go there.
We see this problem most commonly in consumer electronics. The more complicated the electrical power supply is in a device, the more likely it is to absorb signals. In the last 20 years, an explosion of electrical devices has invaded our homes. Computers, video gear, and fancy electronics are more present than years past.
Take the personal computer. These devices contain a complex power supply whose job is to
deliver clean and pure power to the memory chips, hard drives, and other parts in a computer. Electrical noise on the line, if passed to the microprocessor, could cause the computer to lock up and crash. The engineers who design the better quality power supplies construct in traps to filter out and kill electrical noise. Unfortunately, X10 signal look like electrical noise to these devices. The result is that a large percent of the signal is lost to this and other devices leaving a weaker signal for the X10 devices.
The most likely devices to be a signal sucker are:
| Device type | Notes |
| Televisions | Sony, Phillips, Magnavox, Hitachi, Emerson are problem brands |
| Computers | Clone-type computers seem to be more of a problem. Name brands like IBM, Apple, Compaq (to name a few) don't seem to cause problems. |
| Computer monitors: | No-name brands are bigger problems than are big name brands. |
| Plug-in recharger | Notebook computers and cell phones |
| Satellite receivers | Some of the DSS type receivers have been reported |
| Fax machines | |
| Surge-protection power strips | Some Panamax models are a problem |
| Computer UPS's | These are notoriously bad for killing signals |
If you find any devices that create noise, not listed on the chart above, please e-mail our technical support staff.
This is just a partial list that we have complied from callers to tech support. If any conclusions can be drawn, it would seem that devices that include complex electronic power supplies are possible suspects. Other electrical devices like toaster ovens, washing machines, and clock radios will have an extremely negligible effect on the signal.
Distance makes a difference
The closer the signal-sucking device is located to the transmitter, the more effect it will have on the signal. You may not realize it, but your X10 signals not only travel inside your home (on a good day), they also travel to neighboring homes on the same power transformer. However, if you neighbor installs a new big screen HDTV, that happens to kill his X10 signals, it will have a very small effect on your X10 system because of the electrical distance between the two. It will kill his X10 system, so armed with this knowledge you can offer to trade him of this big expensive TV for an old 25" Sony! When the signal sucker and the transmitter were on the same circuit or worse yet, plugged into the same outlet, the effect is dramatic.
How to find your Signal Sucker
You can test for the problem pretty simply. If a device is suspected of causing signal absorption, we call it "Signal Suck" in the Tech Dept., you will need to unplug the device and then re-transmit the signal. If you have a HouseLinc or JDS Time Commander, put it in the signal test mode and it will transmit a continuous series of ON and OFF signals for a single address. It's very important that you don't just turn the device(s) off; you need to unplug them! I once had a computer monitor that absorbed 90% of the present X10 signal, even when it was switched off! Using an inexpensive signal strength indicator like the one on the left, it's a snap to find your sucker.
If the X10 device begins working after the electrical device is unplugged, then you will need a filter on the offending device. Install the filter between the offending device and the wall outlet. The filter will prevent X10 signals from entering the appliance and raise the signal strength of the entire home.
We have these in two sizes on our web site and catalog:
An average home will need between three and five of these filters. In my home, we have filters on all televisions and computers. If you want to shop locally for a filtering device, I'll help you out. The "AC Line Interference Filter" sold by a large ubiquitous electronics store for $12.99 doesn't work; so don't bother with it. If you check out the surge protector strips at your local computer store, look for ones that have "noise filters" in them. Check the specifications carefully; you'll want to find one that begins filtering at 100kHz. If the filtering begins at anything higher than that, say 150kHz, it's not going to help. It should
also have a noise reduction rating of 30db or higher. The Leviton model on the right will filter noise and other nasties from 5kHz to 10MHz with a reduction of 30 to 40dB.
When we speak to our dealer-installers, (who are in the business of installing automation system and not in the 'call-back' business), we encourage them to include some filters as part of the standard package.
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