Broadband
Access of internet through dial up, is very slow even this technology is cheaper but where time become an important factor, there dial up is completely fail. For the faster access of internet a new technology was introduced which is known as broad band internet or broad band internet services. Broad band is a high speed data transfer technology, which increase the speed of data transfer up to that limit, you can make a video conference, download heavy files in seconds, play online games, and can watch movie online. DSL and cable internet connections are classified into broad band internet connection. DSL stands for digital subscriber line, is a internet connection which is used over normal telephone line. By using DSL you can send data and voice at the same time, your phone line is not stay busy while using internet as done before in dial up connections.

Varieties of DSL
DSL connections are available in number of varieties; following are some types of digital subscriber line.

• ADSL (Asymmetric DSL)
• HDSL (high bit rate DSL)
• IDSL (ISDN over DSL)
• RADSL (Rate adaptive DSL)
• VDSL (very high bit rate DSL)
• G.SHDSL (single pair high speed DSL)
• DSL Lite

Short detail of each DSL types is described below.

ADSL
ADSL stands for asymmetric DSL, in this broad band connection the uploading bandwidth and downloading bandwidth are different. Normally this connection is available with 2MB downloading speed while the uploading speed is 128 Kb. This DSL connection is most widely used.

HDSL
HDSL stands for high bit rate digital subscriber line, is a special type of DSL, this connection is not widely used. Only used for special purposes.



IDSL
IDSL stands for ISDN connection over DSL, this connection is 144 Kb standard. This type of broadband is normally used when ADSL is not available. This connection is slow as compared to ADSL but also little more expensive.

RADSL
RADSL stands for rate adaptive DSL, this connection is sub type of ADSL, in this connection the speed of the internet is adjusted. The distance from the ISP and your cable quality can affect on speed of RADSL.

SDSL
SDSL stands for single line DSL, is a broad band connection type in which downloading and uploading speed is same. This connection normally contains 1.5Mbps bandwidth. SDSL connection type is expensive one and not commonly in used.

VDSL
VDSL stands for very high bit rate DSL, this connection is a symmetric type connection and have very high bandwidth. The downloading speed of VDSL is approximately 55Mbps but this connection operates fully if your distance from the ISP is nearly equal to 1000 feet’s. For long distance transmission the rate of VDSL is decrease dramatically.

DSL Lite
DSL Lite is also a symmetric version of DSL.

G.SHDSL
G.HDSL is stands for single pair high speed digital subscriber line is sub type of SDSL, its standard were defined by ITU. This symmetric connection is available with speed range of 192 kbps to 2304 kbps on a single pair line while its speed increased on two pair line. On two pair line the speed range is 384 kbps to 4608kbps.