Sarasota PC Monitor
Tech Talk (4/00)
Home Networks
by Brian K. Lewis, Ph.D.*
Member of the Sarasota Personal Computer Users Group, Inc.Today an increasing number of homes seem to have more than one computer. As a result, rather than purchase multiple printers, scanners, etc., it would seem to be more economical to set up a local network to share these devices. There is even the possibility of sharing the Internet access. The popularity of this idea is reflected in the number of home networking solutions appearing in the marketplace. Companies such as 3COM, Intel, Diamond and others now have home networking kits available.
So there are multiple solutions to the problem of sharing computer resources when you have multiple computers. One solution is to set up a standard Ethernet network similar to that found in small businesses. Windows 9X has built-in networking software for a "peer-to-peer" network. This simply means that the computers will share files and peripherals on an equal basis. This is opposed to the server type network found in many businesses where all the programs and data files reside on one computer. To set up a peer-to-peer network you need an Ethernet card for each computer in the network. You also have to run cables from each computer. If you only have two or three computers to connect you can use a coaxial cable otherwise known as 10BASE-2 or thin Ethernet. This does require that your Ethernet card support this type of cable. You can connect many computers with this system. However, since it is a linear arrangement (one computer connected to the next), when one computer goes down, so does the whole network. The data transmission speed in this type of network is generally limited to 10 megabits per second (Mbps). There is a variation called VGAnylan that operates at 100Mbps. However, it is a proprietary system and more expensive.
The alternative in an Ethernet network is to use a 10Base-T system. Most Ethernet cards are designed for 10Base-T. However, if you have more than two computers, or if your computers are more than seven feet apart, you have to buy a hub for this network. That increases the network cost by a minimum of $50.00. In a 10Base-T network, all the computers connect to the hub. This is frequently referred to as a "star" network. In this setup, when one computer goes down, it does not take down the entire network. The maximum data transmission speed in this network can be either 10 or 100Mbps. The 100Mbps network requires category 5 cable and 100Mbps cards and hubs. Naturally, this raises the overall cost.
If you have only a two-computer network, you can use a crossover cable connected to the two Ethernet cards. There is a limit to the length of this cable. Some specifications indicate it should not be longer than seven feet. You can buy longer cables. However, this increases the probability of data loss. Another possibility for this small network is a direct cable connection. This requires a special serial or parallel cable such as that provided by PC Anywhere or Laplink. Win9X does support this type of connection. I have also seen a USB cable for connecting two computers. In each of these cases, the length of the cable limits the distance between the computers. Generally they need to be in the same room.
Since home computers are frequently placed in different rooms, or even on different floors, network cabling is usually out of the question. For many people the idea of drilling holes in their walls to string wires for their computers just doesn't fly. Fortunately, there is now a solution to this problem, telephone wires. Every home, or apartment, has a built-in network in the form of the telephone wires in the walls. There are a number of companies selling kits that use these wires to connect computers. Intel, for one example has kits that use a USB connection, a parallel connection or a PCI card. 3Com has a similar selection. In both cases, the kits are available with either a 10Mbps or 1Mbps transmission speed. The cost of the any of these kits is in the range of $120 - $190 for two computers. In general, the USB kits tend to be at the higher end of this price range. However, they are also the easiest to use and install, providing you are using Window 98 and have USB ports on your computers. When I say Windows 98, that includes the Second Edition version. You can add additional computers to these systems at about half the price of the kit.
One of the interesting facets of these telephone line networks is that they don't interfere with either incoming or outgoing telephone calls. The companies that provide these kits use a standard developed by the Home Phoneline Networking Alliance (www.homepna.org). This standard takes advantage of the fact that multiple services can be operated simultaneously over a single pair of wires. Each service is assigned a frequency range that is different from all the others. Then, by the use of frequency filters, devices using one type of service can exchange information without interfering with the other services. The voice transmission over your regular telephone line is restricted to a frequency of 20Hz - 3.4KHz. DSL services use the range of 25KHz to 1.1MHz. The home phone line networks use the high frequency range of 5.5MHz to 9.5MHz. There is also a coding system used to identify the home networking data transmission to the receiving system. This system prevents interference with the normal voice calls. That does mean that you can use your telephone to make/receive calls while using your computer network. These networks also allow any computer to access your Internet service. In addition, the software may allow more than computer to access the Internet at the same time. Just remember, if you use your telephone line to connect to the Net, you can't use the line for voice calls at the same time. Also, if you are on a cable or DSL modem, you need to have a "firewall" to protect your network from outside intrusion.
If you have a desire to network your home computers, these phoneline kits are worth considering. You can share files, printers, Internet connections, scanners, etc., with your one voice telephone line. Just remember, like any network, they are not 100% trouble-free. Be prepared to research the manufacturer's web site for information when you run into problems. In fact, it is always a good idea to look for this information before you make any computer-related purchase. :
*Dr. Lewis, a former university & medical school professor, is a computer consultant doing instruction, hardware/software services and system upgrades.
He is available to help you with your home or business computer problems. He does make house calls and can be reached via e-mail at bklew@worldnet.att.net or voice mail at 941/925-3047. :
_______________________________________________________________ Copyright 2000. This article is from the April 2000 issue of the Sarasota PC Monitor, the official monthly publication of the Sarasota Personal Computer Users Group, Inc., P.O. Box 15889, Sarasota, FL 34277-1889. Permission to reprint is granted only to other non-profit computer user groups, provided proper credit is given to the author and our publication. We would appreciate receiving a copy of the publication the reprint appears in, please send to above address, Attn: Editor. For further information about our group, email: admin@spcug.org/ Web: http://www.spcug.org/
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