Phone line networking connects computers in the home by using existing phone lines. The standard for this technology is set by the Home Phone Networking Alliance (HPNA), often referred to as HomePNA. The first incarnation of HPNA, version 1.0, was very slow at 1 megabit per second (mbsp). Version 2.0, developed by Broadcom, boosted that rate to a more acceptable 10 mbps.
Phone line networking uses frequency-division multiplexing (FDM) to create multiple channels for data transfer. These channels operate at frequencies unused by voice carrier signals or DSL modems, making it possible for a single phone line to support all three technologies simultaneously.
The advantages of phone line networking are that it is easy to install, inexpensive and reliable. It delivers datastreams of 10 mbps, regardless of phone use. No additional devices, such as routers or switches, are needed and phone line networking will support up to 25 devices. It is fast enough to deliver video and works on Macintosh computers as well as PCs.
Some disadvantages are that phone line networking requires a phone jack in the vicinity of each computer or the use of extension wires. If large amounts of data will be transferred between computers as a rule, a faster technology like Ethernet (100 mbps) might be desired. Phone line networking also has a physical limitation of 1,000 feet (305 meters) of total wiring, and a coverage limit of 10,000 square feet (929 square meters). In some cases, the installation of a phone line network might cause noise on the voice line. Low-pass filters might be required, available at most electronic stores.
To set up phone line networking, an internal PCI card or external USB card must be installed in each computer. When buying cards for phone line networking, be sure to get cards that are rated for HPNA 2.0 or better. Kits come with one or more cards and software. The total cost is close to US$100 to set up two computers and a printer.
Phone line networking can be a simple, cost-effective solution for setting up a home network. Other technologies include power line networking, wireless, and Ethernet. Each has its advantages and disadvantages, which should be considered before choosing the technology best suited for your needs.
