More bandwidth for the Internet.
So, what is bandwidth? Simply, it's a way to measure the speed of information transfer between any two computers. Bandwidth usually refers to the speed of the Internet, but it can also be used to describe information transfer on a smaller computer network, such as an office LAN. Think of the Internet as an enormous glass and the information on the Internet as water in the glass. Your Internet connection is the straw with which you drink the water. Bandwidth is a way to measure the size of the straw. A very small straw will not allow you to satisfy your thirst, but a reasonably large straw will provide you with ample water. Similarly, an Internet connection with low bandwidth will be painfully slow when browsing Web pages and downloading files, but a connection with lots of bandwidth will allow you to view even the most complex and visually-exciting Web page within seconds.
The big concern is the origin of the bandwidth. Many believe that everything has to be designed to work together within limited space on networks. Their plan is to extend their existing systems with fiber optic lines for costs approaching one million dollars per mile.
Let me just say - computers are not going to work according to these plans. Computers are going to develop in ways as yet undreamed. What can be banked on is change and that change will unerringly move towards less expensive and more functional systems.
The Internet and the intranet are hot today everything - is moving towards faster and wider applications of these technologies. The Internet is a world-wide computer network that allows for file transfer and shared applications. An intranet is a regular wide-area or local-area network (affectionately called either WAN or LAN) which emulates certain features of the Internet.
Asymmetric Digital Subscriber Line (ADSL) is a technology that has been available for about 10 years, and, in 1998, the ADSL technology will take over the marketplace. Integrated Services Digital Network (ISDN) technology is expensive in terms of service costs, largely because the phone companies seem determined to make a windfall on the technology. Dedicated fiber optic lines, the ultimate in bandwidth, are even more expensive than ISDN.
ADSL uses plain old telephone service (POTS) lines to achieve speeds as high as 4.4 Mbps (megabits per second), and should eventually reach speeds between 8 and 50 Mbps. For comparison, POTS modems only run at a maximum speed of 33.6 Kbps (kilobits per second), approximately 1000 times slower than ADSL. ISDN technology has a maximum speed of 128 Kbps, which is approximately four times faster than POTS, but is still 250 times slower than ADSL.
The 'A' in ADSL means 'asymmetrical,' which means that ADSL cannot transfer data in both directions simultaneously at the same speed. ADSL can conceivably transfer data at speeds up to 50 Mbps in one direction, but can only handle 640 Kbps in the other direction. However, most Internet applications only require the user to be downloading data, so the other direction will often not be needed. When the user needs to upload, the ADSL system can simply reverse its direction temporarily and the user will be able to upload at the line's full speed. Moreover, two ADSL phone lines, which are very similar to POTS lines and would cost almost the same, could easily handle simultaneous uploading and downloading at speeds up to 50 Mbps. ADSL is ideal for many applications, including video-on-demand, teleconferencing and high-speed Internet access.
One xDSL technology, called Homogenous Digital Subscriber Line (HDSL), is available now and works over standard POTS lines. HDSL employs inexpensive modems and moves data more slowly than ADSL. However, at 762 Kbps, HDSL is still 6 times faster than regular POTS modems.
What technology are the modem suppliers backing? PairGain Technologies in Tustin, CA is currently working with HDSL. A survey showed that telephone companies predict that 58,000 xDSL lines will be installed during 1997 while original equipment manufacturers predict 421,000 lines. For 1998, telephone companies predict 483,000 lines, and manufacturers predict 1.5 million lines. Dataquest predicts that they will ship 3.7 million xDSL modems by the year 2000.
Why will xDSL modems survive and cable modems not survive? The cost of cable is high, nearly $1,000,000/mile. This cost will have to be borne by the consumer, as with Comcast's planned fiber-optic cable network. In contrast, the twisted-pair lines of POTS are already installed around the country, inexpensive to add, and support the xDSL technology.
Making POTS lines carry an ADSL signal does not require wholesale replacement of existing cabling, rather the development and installation of modems to provide the communications speed boost and open up existing systems to the ADSL bandwidth. Three companies, Analog Devices, Inc., AT&T Paradyne and Motorola Semiconductor are currently testing and developing ADSL modems.
A related technology promises to adapt to wire gauge/length, severe bridge cuts and other variables throughout the worldwide telephone network Called Rate-Adaptive Digital Subscriber Line (RADSL), this emerging technology will run like a regular POTS modem in that it will adapt its speed to local line conditions.
Once the price of ADSL modems drops below $500, which most developers and suppliers agree will happen within the next two years, everyone will have access to this cheap and efficient technology. ADSL will be a very inexpensive way to perform the teleconferencing and high-speed Internet access that currently require expensive fiber-optic cable. Tremendous bandwidth will be accessible by merely connecting an ADSL modem to an existing telephone line.
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|Title Annotation:||Guest Column|
|Publication:||The National Public Accountant|
|Date:||May 1, 1997|
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