Wireless Networks

Although wired networks are the most popular they aren't always the most convenient. When computers are spread far and wide throughout your home, you may think twice about stringing cable up the stairs or drilling holes through walls. Wireless home network kits have entered the market and come in three different flavors: telephone lines, AC power wiring or radio waves.


Phone Line Networks
If all your computers are located within easy distance of a phone jack then a phone line network may be a good choice. Though this technology is called "wireless" it actually uses your home's internal phone wiring to connect one computer to another. Most phone line networks require that all computers be connected to the same phone line. A few manufacturers have hardware that allows you to connect computers on two different lines within the same home.

A phone line can carry multiple signals at different a frequency which is why you can talk on the phone and still use a DSL modem for internet access. Network traffic over phone lines use frequencies higher than DSL or voice bands. The industry standard for this technology is set by the HomePNA (Phoneline Networking Alliance). The HomePNA 1.0 standard transfers at a maximum of 1 Mbps while version 2.0 transfers at 10 Mbps, supporting up to 150 m (500 ft) of wiring between devices. Nearly all homes can use HomePNA 1.0 networks, but low-quality wiring in older homes may interfere with version 2.0 networks.

Interfaces
There are several ways to connect your computer to a phone line network: parallel port, USB, NIC or PC Card. As long as all your network hardware is HomePNA compatible, you can mix and match within a network. So you can have an older computer with a parallel port adapter and a newer one with an Ethernet adapter. HomePNA products are widely available and supported by several different manufacturers.

Performance
In real life, it's unlikely you'll see the maximum transfer rates quoted by the HomePNA. Even HomePNA 2.0 networks are not as fast as a traditional 10 Mbps Ethernet. Depending on your computer, the interface you select and the wiring in your house, performance ranges from 20-70% of the rated speed. Generally, PCI adapters are faster than USB and parallel adapters.

Price
The least expensive option is an internal PCI card which starts around $60 for a 1 Mbps model and $80 to $100 for a 10 Mbps card. USB adapters are slightly more expensive beginning at $100. You can usually save some money by purchasing a kit with two adapters. When you buy a network kit you normally get drivers, software, internet sharing utilities and a manual --removing a lot of the hassle from installation.

Power Line Networks
Since power outlets are more widespread in a home than phone jacks, a network that makes use of electrical wiring could be more practical. Power line networks send data signals through your existing AC power lines. The problem is that data transmission uses the same frequency as household appliances. Consequently, power lines suffer from a lot of noise and interference which can make power line networks unstable and unreliable. This is especially true if your house has old wiring or you operate major appliances while networking.

To date, there is only a handful of network products that uses power lines. Kits with two adapters start at about $200. The set-up is straightforward, but the maximum transfer speed is only 340 Kbps and performance can degrade if your drier or dishwasher is running at the same time. Like the HomePNA, there is a HomePlug Powerline Alliance composed of some of the biggest names in networking. They are developing standards for a second generation of power line network products with 10 Mbps transfer rates and increased reliability.