ADSL Basics

If your computer is still dialing into the Internet from a modem, you may want to consider ADSL

Internet at the speed of sound was a just a dream a few years ago. And the truth is, it remains that way for some folks. The saying goes that you're only as fast as your phone line and in rural areas, it's a very real consequence. A 56k modem may still only transmit at 28.8 kps, for instance.

Broadband, satellite, cable communications have all worked to speed up connections - for a price. However, those monthly charges are beginning to drop and are becoming affordable for a majority of users. The down side, it simply isn't feasible to "connect" through these services in all areas.

DSL stands for Digital Subscriber Line. The concept works off a basic two-wire copper telephone line, splitting voice frequencies on the low end and recruiting the high end for transmissions between computer and the Internet, through an ISP (Internet Service Provider).

With ADSL, which stands for Asymmetrical Digital Subscriber Line, the high end transmissions are designed to provide faster connections. The "asymmetrical" part means that downloads will be several times faster than uploads. This is based on the assumption that most people download more than they upload. For home uses who access videos, music, games, etc., this is a decided improvement. Because it also means that a single phone line can be used for both Internet browsing and talking - at the same time. There is no downtime for either if one or the other is in use.

Where this is disadvantageous is for the person who actually uploads large files. Graphic artists, for instance, might see a slight difference from modem speed, but not enough to be significant.

While ADSL sounds like great new technology using old telephone lines (these are called POTS - Plain Old Telephone Service), not everyone can access the service. First, the line itself must be free of amplification devices called coil loads. These are placed at certain distances along a lone to carry voices - making them clear and amplified. Second, a phone line that goes between analog and digital equipment cannot be used for ADSL. Third, a spliced line - one that is used to connect many customers in an area - will not work. Last, and most important, the customer must be within the vicinity of a Central Office (CO) or transfer station. This is typically three miles.

Service setup can be slow. When setting up, modems must be installed with the hard drive and filters are placed at the phone/wall connection. Many customers do not know if ADSL will work on the line until equipment is installed and access is attempted. It is often at that point the telephone line is deemed unusable.

Another upside is that each ADSL line feeds directly into a service provider's line. That means peak access 24/7. This differs from cable connections that typically are divided among many customers and may slow the entire group down at peak usage times.

There are other types of DSL lines, but these are higher priced and typically used in businesses. SDSL (symmetrical digital subscriber line), for instance, allows equal - and high-speed - access for both downloading and uploading. The phone, however, cannot be used for voice transmissions at the same time.

Modem users will begin finding comparably priced ADSL access in approved areas and it's well worth the research to find out if this is the right upgrade.