Jim,
I think I will pass on Orckit because of the patent infringement liability. The following article says that xDSL will not be available to 40 percent of U.S. households because of copper wire degradation. How can xDSL be the wave of the future if virtually half of the United States market is excluded? See below:
A NEW FAT PIPE
A powerful consortium pushes
a new path to the Internet
Scientific American
April 1998 Edition
In the high-stakes struggle to make the Internet more mainstream, one monumental challenge has loomed from the very beginning. That problem is replacing the thin "soda straws" through which data get to most home users with big "fat pipes."
Until a few months ago, the only fat pipes that seemed to have a reasonable chance of succeeding were cable television lines, converted to convey data through cable modems. Recently, however, three computer giants--Compaq Computer, Intel and Microsoft--threw their considerable weight behind the only real competitor to cable modems. The fat-pipes sweepstakes has become a bona fide race.
This past January the computer colossi announced that they were joining with the large regional telephone companies in the U.S. to form a consortium dedicated to hastening the availability of hardware and software for a technology known as asymmetric digital subscriber line (ADSL). At data rates that are expected to range from about 400 kilobits per second for home users to 1.5 megabits per second for commercial clients, ADSL will be slower than cable-based data services, which offer rates up to 10 megabits per second. But ADSL is a considerable improvement over today's telephone modem, which has data rates below about 50 kilobits per second.
ADSL, too, works over a telephone line but differs in a critical aspect. A conventional modem converts data to an audible signal that is sent on the line's voice band, between zero and 4,000 hertz. An ADSL modem, on the other hand, translates the data to signals in a much higher frequency band, in the hundreds of kilohertz. Thus, a single ADSL connection can be used to cruise the Internet while carrying on a phone conversation. More important, the high frequency permits far higher data rates in comparison with the voice band.
This neat technical picture omits a number of major problems, however. Because the signal degrades as it travels over the copper wires, the length of telephone line over which an ADSL connection can be established is limited. Specifically, the line known as the local loop, which connects a home with a telephone company's central office, cannot exceed a length of three to eight kilometers, depending on the quality of the line and the desired data rate. In addition, the line must consist of copper wires all the way to the home. Rough estimates are that these limitations exclude 40 percent of U.S. homes.
Moreover, if the service becomes as popular as some projections suggest, local telephone central offices could become rather crowded. Each ADSL connection requires a modem at both ends. These modems currently cost several hundred dollars, and the need to install thousands of them in a central office could present a storage problem. The problem would be mitigated, presumably in the near future, when it becomes possible to put an entire ADSL modem on one integrated circuit. Another challenge to be surmounted involves devices called loading coils, which have been installed on lines to improve the voice signal. Unfortunately, they also block the ADSL signal. "It's not going to be easy to turn ADSL into a competitive product," comments Jay A. Rolls, director of multimedia technology for cable giant Cox Communications.
One of the biggest problems of all, Rolls adds, may be economic. Many telephone companies now make handsome profits leasing T1 lines, which cost anywhere from $350 to $1,000 a month or more and offer data rates of 1.544 megabits per second. With ADSL, however, a company will be able to get comparable capacity with one or two high-end lines--and at a cost well below $200 per month.
When that happens, why would anyone want a T1 line? For one, T1 lines do not have the length limitations of ADSL, notes Greg Gum, who is in charge of the country's largest ADSL trial, at the regional telephone company U S West. In addition, Gum says, many business users need capacity far in excess of even T1 rates, and such capacity would be impractical to implement with ADSL. Finally, that "A" in ADSL, standing for asymmetric, reflects the fact that a user can receive data at high rates but can send only at much lower ones. "I think it's a bit strong to say, 'There goes the T1 market,'" says Joseph Bartlett, who studies the Internet for the Yankee Group, a market analysis firm.
The new ADSL consortium is hoping to have widespread deployment of the technology sometime in 1999. In the meantime, however, essentially all the regional telephone companies have trials that are either ongoing or planned for the near future. The most advanced is U S West's, which is called MegaBit and was unveiled in the Phoenix area last September. Home users are paying $40 a month for a 192-kilobit-per-second connection (to be increased to 256 kilobits per second in the near future, Gum notes), plus $19.95 for Internet service, $199.95 for the installation and about $200 for the modem. The prices are somewhat higher and the data rates significantly lower than those for the competing cable-modem Internet service, offered in the same area by Cox Communications. U S West is also offering higher-speed ADSL services aimed at businesses; a 704-kilobit-per-second connection (to be upgraded to 768 kilobits per second) costs $125, plus fees for Internet service, installation and the modem.
--Glenn Zorpette |
