A new technology called high-speed Digital Subscriber Line (DSL) has emerged onto this scene. DSL, which encompasses several different technologies, essentially allows the extension of megabit bandwidth capacities from the service provider central office to the customer premises on a customer by customer basis over the existing copper cabling, without the need for massive infrastructure replacement and at very reasonable costs. These new DSL solutions satisfy the business need to provision the network in a fast, cost effective manner, while preserving the infrastructure and allowing a planned migration into newer technologies. DSL has the proven ability to meet the customer demand for high bandwidth right now, at costs that make sense.

It is clear that the telecommunications industry has developed, and deployed, cost effective technologies that have enabled them to create global, high bandwidth, interoffice networks capable of supporting the demands of the information age. This network infrastructure, however, has, until now, been lacking one significant component--a ubiquitous low-cost, high bandwidth access circuit from the customer premises to the local service provider. Called the local loop, this circuit element has been an historic bottleneck, inhibiting customers from taking advantage of the rich array of currently available high bandwidth network services. The pervasive copper cable infrastructure already deployed throughout the local access landscape has, until now, been incapable of supporting the higher bandwidths required by the growing traffic demands of the customer. In response, the industry has promoted the development of technologies and products that address this need for higher bandwidth solutions in the local loop. The most significant of these developments has been DSL.



Who is DSL for?
Home users
It is readily apparent to teens, seniors, teachers, and professionals in all fields, that the Internet is where it's happening! The use of web sites, home pages, FTP, chat areas, URLs, E-mail, has grown at a tremendous rate. The taste for graphics, sound, live interaction, two way video, and ubiquitous entertainment are already unsatisfied. Demands for better and quicker and richer and prettier, are placing demands on the local telephone infrastructure as nothing ever has in the past! The Internet is certain to be as pervasive as the telephone itself; and the demand for megabit rates bandwidth right to the desktop device is certain

Businesses
Businesses have had an equally intense preoccupation with the Internet. Businesses are currently formulating plans to use the Internet as an integral part of their networking strategies, with customer and vendor interactions, advanced web site developments, and more. On top of this, is the move towards corporate-wide Intranets. Intranets are internally developed and deployed intra-company networks that operate in essentially the same way as the Internet itself. Major graphic intensive applications, video, sound clips, large scale database deployment, and more, are all becoming mission critical for businesses as they develop revolutionary new business models. Businesses are also implementing new applications, which, by their very nature, greatly expand the need for bandwidth capacity. These include collaborative processing applications as well as desktop video conferencing, transmitting large graphic files, and real time computing.

DSL Solutions

DSL refers to a set of similar technologies that provide high bandwidth over copper twisted pair local loop cable, without amplifiers or repeaters along the cable route. It refers to the connection between the customer and the first node within the network. DSL is provided over non-loaded local copper loops1 which are the overwhelming majority of cable facilities in a telephone exchange area. DSL technology is compatible with existing services, such as POTS (plain old telephone service), ISDN, and DDS, and will work over the majority of copper loops existing today.

DSL Supports Industry Standards

DSL technology supports industry-standard transmission formats and bit rates, such as T1 (1.544 Mbps) and E1 (2.048 Mbps), and is sufficiently flexible to support additional rates and formats as they are defined (e.g., 6 Mbps asymmetric for high speed data and video). DSL technology coexists in the loop with voice. As a result, all types of services, including the existing voice, video, multimedia, and data services can be carried without developing new payload strategies or standards from scratch. This is critical to seamless deployment of higher bandwidth-based services.

Modem Like Technology

DSL is a modem-like technology in that it requires an DSL terminating device at each end of the cable pair which accepts a data stream, usually in digital format, and overlays it onto a high speed analog signal. The three modulating techniques currently in common use for DSL divide the signal frequency range into three basic elements to carry POTS as well as the upstream and downstream high bandwidth signals. These three modulating schemes are 2B1Q, carrier-less amplitude phase modulation (CAP), and discrete multitone modulation (DMT).

As we consider the need to support the growing demand for Internet access combined with telecommuting and LAN interconnectivity, we can see that DSL offers an amazingly serendipitous opportunity. Because DSL technologies have matured so quickly and have established a secure, dependable, and broad penetration into the industry, high bandwidth applications can now be supported in a cost effective and competitive basis.

Home • Search • Services • Support • Contact • Info