Types of DSL

Distance from the telephone exchange DSLAM system is more restrictive for the higher data transmission types of DSL.

ADSL (Asymmetric Digital Subscriber Line) – This is DSL for the home user. This technology will enable faster data transmission through standard copper telephone lines. It is capable of accomplishing this through utilizing frequencies within the telephone cables that the human ear cannot hear. this allows for you to use your phone at the same time. This signal is unable to travel very far over standard telephone cables, typically under 5 km.

SDSL (Symmetrical Digital Subscriber Line) -  SDSL is generally targeted at small and medium sized businesses, that may host a server on site. The major difference between ADSL and SDSL, is that SDSL maintains the same upstream and downstream transfer rates (hence the symmetrical), whereas ADSL will have a smaller upstream than downstream transfer rate. The major downside to SDSL for the home user being the fact SDSL will consume the entire phone line, thus not allowing you to speak on the phone line. it’s also very expensive.

IDSL (ISDN DSL) - IDSL will transmit data digitally (unlike ADSL/SDSL which is analog). It’s essentially used to provide a broadband service to customers who don’t qualify for ADSL or SDSL service. The IDSL signal is capable traveling to customers who may be up to 10 km away from the telephone company.

ITU G.992.5 (Also Known As ADSL2+) - ADSL2+ will extend the capability of the basic ADSL service by doubling the amount of downstream data transfer. These rates can reach heights of 24Mbit/s downstream and 1 Mbit/s Upstream, based on the distance from the digital subscriber line access multiplexer to the users home.

VDSL2 (Very High Speed Digital Subscriber Line 2) -  VDSL2 is the next generation of DSL. It'll create channels within the available bandwidth then constantly monitors their integrity, and switches the channels when the signals become degraded. This ensures your data is shifted through the best route giving you the fastest possible connection. Unfortunately, the signal will deteriorate from its theoretical maximum very quickly based on the distance you are from the source.

SHDSL (Symmetric high-speed digital subscriber line) -  SHDSL is very similar to SDSL. It uses a more advanced coding technology (TC-PAM). It is the first standardized multi-rate symmetric DSL. It is ideal for businesses that require reliability and high speed connectivity in both upstream and downstream.

RADSL (Rate-adaptive DSL) -  RADSL is a variation of ADSL. RADSL incorporates technology that will constantly adjust the upstream data transfer rate based on the length and quality of the line. This is done in an attempt to maintain a certain downstream speed.

HDSL (High Data Rate Digital Subscriber Line) -  HDSL incorporates technology that takes advantage of a higher frequency spectrum of copper twisted pair cables. HDSL has been developed as a more advanced technology for high-speed, synchronous circuits generally used to interconnect local telephone company systems, but also to carry high-speed corporate data links and voice channels on T1 lines.

Etherloop - Etherloop is a next generation DSL technology. It utilizes the technology of DSL and Ethernet. It'll allow for the ability to use the telephone and transmit data at the same time on a standard phone line. The theoretical maximum for Etherloop is 6 megabits per second over a distance of 7 km.

Edited by Administrator - 05 Apr 2007 at 6:36pm

thanks, i found it too...