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Mirror Magazine

Techno Page - By Harendra Alwis
Power- line networking
Networking, as many people know, can be quite a complex and cumbersome job more often than not. But did you know that you could actually use your power line to put up your own "home computer network"? Power-line networking is one of several ways to connect the computers in your home. It uses the electrical wiring in your house to create a network! Don't you think the news itself is "electrocuting"?

The convenience is even more obvious because while not every room has a phone jack, you will always have an electrical outlet near a computer. In power-line networking, you connect your computers to one another through the same outlet, because it requires no new wiring, and the network adds no cost to your electric bill. Power-line networking is the cheapest method of connecting computers in different rooms.

There are two competing power-line technologies. The original technology is called Passport, by a company named Intelogis. A newer technology is called PowerPacket, by Intellon. PowerPacket has been chosen as the standard for power-line networking.

With a power-line network in place, a printer or any other device does not have to be directly connected to a computer or physically near any of the computers in the network.

It doesn't require a card to be installed in the computer although there are companies working on PCI-based systems.

Power-line networks are fast, rated at 14 megabits per second (Mbps). This speed allows for new applications, such as audio and video streaming, to be available throughout the house. Furthermore, it "avoids" disruptions in the power-line, maintaining the network's connections and speeds. It does not limit the features of your printer and can be compatible with many operating systems (depending on driver availability).

Intellon's PowerPacket technology, which serves as the standard, uses an enhanced form of "orthogonal frequency-division multiplexing" (OFDM) with forward error-correction, similar to the technology found in DSL modems.

If noise or a surge in power usage disrupts one of the frequencies, the PowerPacket chip will sense it and switch that data to another carrier. This rate-adaptive design allows PowerPacket to maintain an Ethernet-class connection throughout the power-line network without losing any data.

Along these lines, Intellon's approach to power-line networking is highly scalable, eventually allowing the technology to surpass 100 Mbps.

The physical connection between each computer and the Intelogis power-line network uses the computer's parallel port. A wall device is plugged directly into the electrical outlet (it will not operate properly if plugged into a surge protector).

A parallel cable is plugged into the wall device and into the parallel port of the computer. The power-line network must be the last item connected to the parallel port. For this reason, if you have anything else connected to the parallel port, such as a scanner or Zip drive, it must have a pass-through for the parallel port. Unless you have a second parallel port on your computer, your printer must be connected to the network through a wall device of its own. Something to keep in mind is that current power-line networks do not support bidirectional printing. "Bidirectional" means that data is sent in both directions, allowing your printer to send information back to your computer, such as how much ink is left and if there is a paper jam. This will not keep your printer from working, but it is worth noting that you will lose the use of such features.

Initial PowerPacket devices will connect via a USB or Ethernet cord from the computer to a small wall adapter. Subsequent devices will have the circuitry built in, meaning the only connection needed would be the power cord. Once the physical connections are made, installation of the software is quite easy. The software automatically detects all nodes (computers and printers) on the network. The included proxy server software allows you to share the Internet with your other computers. You can easily add computers by simply plugging a new adapter in and installing the software. Additional printers can be added using the printer plug-in adapter. File and printer sharing is done through Windows.

There are two common types of home networks: peer-to-peer and client/server. Client/server networks have a centralised administrative system that provides information to all of the other devices. Peer-to-peer means that each device can talk directly to each other device on the network without consulting a central system first. Intelogis' Passport technology uses a client/server network. The first computer that you install the software on becomes the Application Server. In essence, it is the director of the network, controlling the flow of data and telling each device on the network where to find the other devices. Intellon's PowerPacket technology uses a peer-to-peer network.

Intellon's PowerPacket technology is compatible with wireless solutions, making power-line an ideal option to serve as the backbone for a multi-technology home network. In this case, you will not have to discard any existing network solutions in favour of a new standard. The one common thread among all of the networking options is the need for power. While a wireless solution may indeed eliminate the need for wires, its access point is still going to be plugged in at some point. That power cord, for example, can tie the wireless network into the home's overarching power-line network.

Even with Intellon's 14-Mbps solution, PowerPacket technology is expected to achieve even greater speeds and capabilities. So get your multi-player games ready and plug yourselves in through the electrifying world of power-line networks.
Source of information CNET.COM.

Improve your computer literacy
Access Time - Time interval between the instant that a piece of information is requested from a memory or peripheral device and the instant the information is supplied by the device. With hard disks or compact discs, maximum access time is measured as the time it takes to move from one end of the disc to the other, find a piece of information, and transfer that information to RAM.

COM Port - A serial port for attaching modem, plotter, printer, or mouse to a system. There are usually 2 COM port connectors: a 9-pin (DB-9) for the mouse, and a 25-pin (DB-25) for a plotter or external modem.

DDE - Dynamic Date Exchange: a mechanism used in Windows to transfer data between two applications or two separate instances of the same application. Windows itself uses DDE for a variety of purposes, from opening documents in running applications when a document icon is double-clicked in the shell to obtaining programme icons for DOS applications. DDE is also used to support OLE. See also OLE.

Firmware - Permanent instructions and data programmed directly into the circuitry of read-only memory for controlling the operation of the computer or peripheral devices. Distinct from software, which is stored in read/write memory and can be altered.

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