The History of DSL Internet AccessA Race for Technological Speed
2004.05.04 14:58 by Gareth Marples
The technological race is a fast-paced one indeed. Improvements are constantly being sought. What had at one time seemed to be amazing advances quickly became yesterdayís news. But have you ever wondered where it all started? Has DSL (Digital Subscriber Line) always moved at this speed? This history of DSL Internet access will show just how quickly new technology became old.
Any history of the transmission of data begins with Alexander Graham Bell and Samuel Morse, two pioneers who developed the idea that data could be transmitted through copper wire. Of course, they had no idea of the scope of their findings, or where they would actually lead. However, the principles had been laid.
The Internet brought a need for speed
The principles demonstrated by these two great pioneers, Bell and Morse, were instrumental in developing a path for the ever-increasing volume of data transmitted over the Internet. In the late 1980s, Joseph Lechleider, of Bellcore, demonstrated the feasibility of sending broadband signals, establishing his place in history as the originator of broadband technologies. He developed the idea of asymmetry (the A in ADSL), which suggested that a higher rate of data could be sent in one direction. Putting it simply, this was the beginning of the move from analog to digital.
The first efforts of this new technology created ISDN. ISDN, which stands for Integrated Services Digital Network, is a system of digital phone connections which allows voice and data to be transmitted simultaneously across the world. The result of this is that more data could be transmitted at the same time, thus creating more speed. And remember, speed was (and still is) the goal.
John Cioffi, who eventually became a professor at Standard Universityís Department of Electrical Engineering, developed DMT (discrete multitone), a method of separating a DSL signal into 256 frequency bands or channels. Cioffi founded a company called Amati, who, in 1993, designed equipment to perform this task. And this equipment was dramatically better than its competitors in Bellcore testing and became the most common standard.
The earliest variation of DSL to be widely used was HDSL (High bit-rate DSL) which gave an equal amount of wideband digital transmission in both directions. HDSL technology was developed in the early 1990s, making it one of the oldest forms of DSL. It was used between the telephone company and a customer, and also within a corporate site. HDSL service provided equal bandwidth for both downloads and uploads, but required multiple phone lines to do this.
DSL changed horses in the middle of the stream
So now the technology was available to achieve the dream of delivering video-on-demand, an idea that had high hopes for the future. At the time, cable companies were promising the possibility of 500 channels and video-on-demand (VOD) could compete with this. However, the idea didnít catch on and the industry never really fulfilled its desires.
As the idea of VOD phased out, DSL emerged much differently than was originally expected. Personal computer users needed high-speed access to the Internet, especially in the corporate domain. Considering the fast pace of business and the amount of networked computer systems, high-speed DSL became the solution.
DSL now presented an opportunity to telecommunications companies to meet their customer demand for faster data access on the Internet. Everyone wanted to get in on the act. And to keep order, the Telecommunications Reform Act of 1996 was introduced in the United States, allowing local phone companies, long-distance carriers, cable companies, radio-TV broadcasters, Internet service providers and telecommunications equipment manufacturers to compete in each otherís markets. The race to provide faster data transfer was on!
DSL technology expands
DSL had achieved its original goal to bring high-speed information to homes and businesses over ordinary copper telephone lines. Now, as technology advanced, other forms of DSL became available. XDSL became the common term for the whole DSL family, with variations like ADSL, RADSL and VDSL following.
ADSL provides greater bandwidth for so-called downstream (from provider to consumer) traffic at the expense of lesser upstream (from consumer to provider) bandwidth. ADSL takes advantage of the typical pattern of Internet access by home users who frequently download large amounts of Web site data but upload relatively small amounts of data.
RADSL (Rate-adaptive DSL) is an ADSL technology utilizing software to determine the rate at which signals can be transmitted on a given customer phone line and adjust the delivery rate accordingly.
VDSL (Very-high-data-rate DSL) is a developing technology that promises much higher data rates over relatively short distances. It was developed to support exceptionally high-bandwidth applications such as High-Definition Television (HDTV). To perform at this speed, VDSL relies on fiber optic cabling. Itís designed to work more as a business service than as a consumer service.
Could DSL survive long-term?
As we mentioned before, technological advances are carrying DSL with them at a fast pace. But complaints like unavailability in certain areas, and slow and interrupted service challenged the industry Ė subscriber growth rates slowed. But just when it seemed that all was lost, the situation brightened.
First, broadband DSL demand caught fire in the Far East, which, according to industry analyst firm Point Topic, had nearly 8 million DSL subscribers at the end of 2001. This was just a part of the explosion of the global DSL subscriber base to 18.7 million users at the end of 2001. Despite some peopleís earlier doubts, things were turning around for the DSL industry.
Now, many of the earlier technological hurdles have been or are in the process of being overcome. The regulatory framework for broadband continues to evolve, slowly but surely reducing the uncertainty associated with investment in broadband facilities. DSL availability is vastly improved. All kinds of useful and interesting things are now available for people to do with their high-speed DSL connections. Look at just a few ways people can use the Internet to add value to their lives:
Do you think thatís enough reason for the DSL industry to be happy? Absolutely! DSL has become a part of our everyday life. DSL has joined that group of modern conveniences that we didnít think we needed but, now that we have it, we canít do without it!
About The Author
Gareth Marples is a successful freelance writer providing valuable tips and advice for consumers purchasing or researching DIRECTV TV DSL, web hosting services and free cell phone tone. His numerous articles offer moneysaving tips and valuable insight on typically confusing topics.
This article on the "History of DSL Internet Access" reprinted with permission.