Creating a Networked Home Without Rewiring
This is an article for people who want to save money, who want to get their network running fast, and who don't want to spend a lot of time learning about networks. The solutions are easy to implement, but they come at a cost. None of these solutions run as fast as high-speed Ethernet; although I've read about some systems that will eventually support 100+ Mbps speed, they commonly support 312 Mbps speeds today. Most games run fine, but other programs won't. If you want a solution that will let you make backups of all the machines in the house and help the kids get their homework done while you work with reports from the office, this is the article for you. Many of these systems also let you control deviceseverything from an alarm system to your sprinkler to the stereo in your family room.
There aren't as many people today in office buildings as there were in the pastat least, not on a consistent basis. Many people now have a home office that they use once or twice a week to work at home. In addition, it's not uncommon to see multiple computers in the home. The one used by mom and dad provides support for the systems used by the children. Because of these changes in the computing environment, many people are looking for networking solutions that will work in their home but not cost a mint or wreck the house. Most of these solutions fall into a relatively new category of equipment known as small office/home office (SOHO for short).
You can also choose to go wireless. While wireless is a great solution for many, it does have a few drawbacks, which I discuss at the end of this article. The main purpose of this article will be to cover wired options for your home, for folks who can't or don't want to go with a wireless solution.
Unlike offices, where false ceilings, cubicle stanchions, and hollow walls offer places to put cables, a home often has permanent ceilings and voids with plenty of obstacles. Running a cable of any kind can prove frustrating. In some cases, the only way to get a cable run is to tear out part of the wallsomething a landlord will look upon with disfavor. (If you own the home, you might decide it's worth the effortbut then change your mind once you see the mess this kind of change creates.) Of course, you could always leave all those lovely cables exposed, but the results are hardly worth the effort, and exposed cables present a number of potential hazards that many people don't want to face.
Fortunately, your home probably already contains all the cable you need to transfer data from one machine to another. Every electrical outlet is part of a web of cabling that encompasses the entire house. A house-wiring network makes use of this feature to get around the problem of running cables in the home. Data moves from receptacle to receptacle, just as it would with standard network cable. This solution doesn't work very well for commercial applicationsit's definitely designed for the SOHO environment.
Of course, just having cabling in place won't allow the network to run. All of these systems require a special plug-in box that isolates the computer from the voltage the house wiring is designed to carry, but allows the computer to transfer signals. One end of the box has a standard two- or three-pronged receptacle plug. The other end has a cable with an adapter on the end that plugs into the computer.
The appeal of the house-wiring system is that it's easy to set up and configure. If anything goes wrong with the plug-in device, you simply pull the old one out and plug a new one init's akin to changing a light bulb. The only difficulty you might encounter is installing the software. While the vendor normally automates this process, you might run into configuration problems in some rare cases.
Using house wiring is one of the more popular alternative networking technologies because it requires so little work on the part of the installer. Some systems don't even require a three-prong outletany two-prong outlet will do. This feature makes some systems acceptable for any house, no matter how old, as long as it has wiring of some kind. Most people will find that setting up this alternative network takes about 10 minutes. You begin by plugging the two plug-in boxes into outlets. Connect the other end to the computer and complete the process by sticking a CD-ROM with the required software into each machine. Once both machines have the required software in place, they should be able to communicate. The only decision that the installer may need to make is which plug to use on the back of the computer.
There are four methods used to make the connection to the computer. The method you choose will depend on how much you want to spend and your networking needs.
The fastest data-transfer method is to connect the plug-in box to a standard network interface card (NIC). Of course, this is also the most expensive method, because you have to buy the NIC in addition to the plug-in box. The theoretical speed of this connection is anywhere from 10 Mbps to 100 Mbps depending on your setup, but you'll rarely get it because of the poor performance characteristics of house wiring. One of the better offerings in this category comes from Linksys. You can get everything from single Ethernet ports to complete kits.
The second-fastest method, at a guaranteed 12 Mbps, is to make the connection to the USB port on the computer. Newer USB ports can get up to 14 Mbps; but, again, it depends on how you have the system set up and what operating system you use (older versions of Windows, for example, don't support high-speed USB connections). Unfortunately, the plug-in requires special intelligence for the USB port, which raises the cost of the system, so it's not as popular as other methods. One of the more interesting selections in this category is the Belkin F5D4050 Powerline Adapter. It features a 14 Mbps transfer rate and 56-bit DES encryption, so nosy neighbors can't intercept your communication.
Older connection methods rely on the parallel or serial ports on your machine. You'll have a hard time finding certified products for these options, but they do exist. The advantage of using a parallel port is that the plug-in requires no special intelligence and you can still get around 360 Kbps transfer rate.
A serial port connection is the slowest method, at a maximum 115 Kbps transfer rate. All of these methods provide better performance than the maximum dial-up speed of 56 Kbps, though, so even gamers should be happy with the results.
Transfer rate isn't the only concern when connecting two machines. You also need to consider a factor called latency, which is the time it takes for one machine to respond to a request from another. House wiring has extremely poor data-transfer characteristics, and there's a chance that the other machine will have to ask for the same data several times before it actually receives a good copy. This means that the time required to transfer a single piece of information (called a packet) increases dramatically as the quality of the electrical cable decreases. A standard 10 Mbps Ethernet network has a latency of about 1 ms for a short cable. A house wiring network has a typical latency of 40 ms, but can be has high as 400 ms if the wiring in your home has a lot of flaws (such as kinks). Unfortunately, there isn't any way to determine what the latency of the network connection will be until you connect everything. In some cases, you can fix a latency problem in a home wiring network simply by moving the plug-in to another receptacle.
A potential concern for this networking technology is the voltage on the other side of the plug-in. If the plug-in should fail in such a way as to connect the house current directly to the parallel or serial port of a computer, the excess voltage will most likely destroy the port and damage the computer. I've never heard of this particular problem happening. It would seem that the vendor selling the kit would ensure the plug-in includes safety measures to guard against this problem, but it pays to check the vendor documentation to be certain.
Another concern is that lightning will strike and damage the system. You should plug your computer into a surge suppressor to guard against this problem. However, there isn't any guarantee that the plug-ins will be able to communicate through a standard surge suppressor for all wiring kit designs. Look for a house wiring kit that includes a surge suppressor that you can use with the kit. This special surge suppressor will allow a higher data-transfer rate and still protect your system from harm. If the house-wiring network kit that you choose doesn't include a surge suppressor, check with the company to ensure that your standard surge suppressor will work. You can partially overcome this problem by asking your electrician to install a whole-house surge suppressor. This device connects to the main lines coming into the house and shouldn't interfere with the connection between computers. A side benefit is that the device can potentially block your computer signals from exiting the house, so sneaky neighbors can't access your network.
Now that you have some idea of how these house-wiring network kits work, let's consider specific vendors. The best place to begin your search for qualified vendors is the HomePlug Powerline Alliance. All the vendors listed on this site offer certified equipmenta must if you want to protect your computer investment. When you want to add various kind of home automation to your network setup, check the X-10 ActiveHome product list.