difference between the different DSLs around?

[Wuming]

anyone care to explain to me the difference between xDSL, ADSL, and whatever else there is?

thanks!

 

[KameLeon]

[*]ADSL (Asymmetrical Digital Subscriber Line)
The most typical of the xDSL family for the home user. The "asymmetrical" part in ADSL comes from the way data is transfered on the DSL line to your house. With ADSL the downstream rate (or rate at which you are receiving data) is usually much faster than the upstream rate (rate at which data is leaving your computer).
Typical data rates with ADSL are 128 Kbps - 1024 Kbps upstream while downstream rates can range from 384 Kbps - 8192 Kbps (8 Mbps). The technology was made this way because typical home users generally transfer ten times more data downstream than upstream.
A major downside to ADSL is that it is not widely available. Only about 50% of the United States can actually get ADSL. Also you can only live as far as 18,000 feet from your ISP's central office to receive ADSL.
[*]SDSL (Symmetrical Digital Subscriber Line)
Also known as "Single-pair Digital Subscriber Loop" because it only needs one pair of copper wires to work. SDSL transfers data in both unstream and downstream directions at the same data rate. Businesses that transfer files often between buildings that are separated by a large geographical area use SDSL because of the symmetric data transfer capabilities.
Typical data rates with SDSL are from 192 Kbps - 1.5 Mbps.
[*]IDSL (ISDN DSL or DSL over ISDN)
IDSL is really a new form of ISDN. A dedicated line is required to use IDSL just as ISDN. Benefites of IDSL include an extra 16 Kbps over ISDN and with IDSL you can be as far as 36,000 feet away from your IPS's Central Office.
Usually IDSL is offered as a low end bit rate option for businesses that need a faster access line but are located too far from the IPS's Central Office to get other forms of DSL.
[*]HDSL (High bit-rate DSL)
One of the first DSL flavors that was developed as a faster cousin to ISDN. HDSL needs two pairs of copper wires to opperate.
HDSL offers speeds of 1.544 Mbps (T1 speed) in both directions, but because of the additional wires needed to obtain this speed, HDSL is more expensive to install, so it is not as widely available.
[*]VDSL (Very high bit-rate DSL)
VDSL is known basically for its blazing fast downstream speed of 52.8 Mbps and upstream speeds of 2.3 Mbps. Fiber optics is used for VDSL, and very short copper loops to help keep the data rate high.
The only problem with VDSL is, it is limited to very short loop lengths, and the technology behind it is not yet ready to support the need of most people.
[*]RADSL (Rate Adaptive DSL)
RADSL is flexible because the sync rates can be adjusted as line conditions change.
With RADSL data rates of 2.2 Mbps downstream and 1.0 Mbps upstream can be attained.

 

[BarbeQueGuy]

Here is a good site that can answer any other questions that you may have.
DSL Reports.COM

 

[jonny67]

there are a few different types.

the most popular is ADSL (asymettric digital subscriber line) up to about 6 megabits/second i think

Others are HDSL (High bit rate DSL) and VDSL (Very high data rate DSL).
VDSL can only be used within about 300m of an exchange but gets up to 50megabits/second
HDSL is somewhere in between but also has distance restrictions.

ADSL is the most popular because you only need to be with 5km of an exchange to get about 1.5 megabits/second. The closer you are the better!!!!!!!!!!!

There's also one called RADSL but i'm not sure what it is.

I have ADSL with a 5.8 megabit connection to the exchange and i can get a megabyte in about 3 seconds from a server in the US.

 

[Wuming]

thanks guys! these are good!