Home

Teaching

Service

Curriculum Vita

Courses on the Web

Lane Report Columns

College Technology

Search Resources

Technology Links

Music Links

The Music In Me

School of Journalism
and Telecommunications

College of Communications
and Information Studies

Top-Speed Transmissions
The Asymmetric Digital Subscriber Line has the potential to make a major impact

It was just in the last couple of months that I related to you a fair amount of information concerning Integrated Services Digital Network (ISDN). If you'll remember, ISDN is a service that allows you to make digital use of your analog phone line to achieve 128 kbps of bandwidth for domestic purposes such as web-surfing and for business purposes such as credit card authorizations and transactions. Of course, the one constant in the telecommunications industry is change, and there is yet a new service coming down the pike that could really transform the way we work and play.

Asymmetric Digital Subscriber Line (ADSL), like ISDN, is a digital service that uses the existing twisted pair copper wire that runs between your phone and your local phone company's home office. The difference between ISDN and ADSL, however, is one of several orders of magnitude. Solely in the context of Internet access, ADSL will open new doors for users, especially once ATM (another acronym which may deserve a column of its own) is introduced to the Internet backbone -- and the Internet is only part of the picture.

While current analog modems operate at 28.8 kbps, 33.6 kbps, or 56 kbps, ADSL will provide you with up to 800 kbps for an upstream channel -- that's for your transmission to elsewhere -- and an astonishing 1.5 Mbps to 9 Mbps for a downstream channel -- web surfing, for instance. That means that the low end of the downstream range is equivalent to a T1 phone line, the industry standard for business data transmission, while the high end is in the range of Ethernet LAN speeds. These kinds of transmission speeds will make it possible for a whole new generation of telecommuters to leave the workplace permanently and stay at home, thus enabling significant reductions in real estate and physical plant overhead for many businesses.

Another use for ADSL, the one for which it was originally intended at its inception ten years ago, is interactive video. That includes movies on demand, time-shifted television shows, video games, video catalogs, and video information retrieval. The major competition for the provision of services such as interactive video and fast Internet access comes from the cable companies, via cable modems, but there is no way that the cable companies can come close to providing the nearly-universal access that nearly 700 million phone lines can.

So how far are we from realizing the benefits of ADSL? Currently, the only publicly available service in the United States is in Chicago. However, a group of telecommunications companies called the Joint Procurement Consortium, of which BellSouth is a member, has endorsed the ADSL technology and is moving ahead with market trials throughout 1997. The Consortium, which controls 45% of the copper wire subscriber lines in the U.S., plans to deploy over two million lines over the next five years. Of course, a number of other telcos will no doubt be jumping on the band wagon.

Interestingly enough, the major obstacle to the widespread advent of ADSL is not a technical problem, but a regulatory one. The Telecommunications Act of 1996 requires Internet Service Providers (ISPs) to resell their services to local competitors so that an open and competitive market is maintained. However, many new competitors are spin-off companies of the major telcos -- therefore the telcos cannot sell services to them without facing anti-monopoly action from the FCC. Once in place, cost to the consumer shouldn't be a tremendous drawback -- it could be as low as $60 per month for a T1-speed line, compared to about $400 per month for the real thing.