Various Types of DSL Boardband Internet Connections

There are a variety of flavors when it comes to Digital Subscriber Line (DSL) broadband Internet connection. DSL is a technology that brings high bandwidth Internet connection to homes and businesses over ordinary copper telephone lines. DSL technology allows data transmission at speeds much faster than the best available analog and digital modems. We'll explain a few of the variety of DSL connections below.

DSL is a generic term used for a family of related technologies, including RADSL, ADSL, SDSL, IDSL, and others. The leading DSL technologies being deployed today include:

RADSL - (Rate Adaptive Digital Subscriber Line)

  • Most robust business DSL available today;
  • Developed to overcome line impediments;
  • Automatically adjusts for environmental conditions; - Because RADSL is a type of SDSL, it supports symmetric (equal downstream and upstream) data transmissions up to 768K.

ADSL - Asymmetrical Digital Subscriber Line
ADSL supports a range of asymmetric (higher downstream than upstream) data speeds that can reach up to 7 mbps downstream and 1.5 mbps upstream. ADSL can deliver simultaneous high-speed data and telephone service over the same line.

ADSL Lite (or G.lite)
This is a lower speed version of ADSL and provides downstream speeds of up to 1Mbps and upstream speeds of 512 kbps, at a distance of 18,000 feet from the service provider’s premises. It is intended to simplify DSL installation at the user’s end.

R-ADSL - Rate-Adapative Digital Subscriber Line
The R-ADSL provides the same transmission rates as ADSL, but an R-ADSL modem can dynamically adjust the speed of the connection depending on the length and quality of the line.

HDSL - Hight Bit-Rate Digital Subscriber Line
The HDSL provides a symmetric connection, that is, upstream speeds and downstream speeds are the same, and range from 1.544 Mbps to 2.048 Mbps at a distance of 12,000–15,000 feet. Symmetric connections are more useful in applications like videoconferencing, where data sent upstream is as heavy as data sent downstream. HDSL-II, which will provide the same transmission rates but over a single copper-pair wire, is also round the block.

IDSL - ISDN Digital Subscriber Line
The ISDN Digital Subscriber Line provides up to 144 kbps transmission speeds at a distance of 18,000 feet (can be extended), and uses the same techniques to transfer data as ISDN lines. The advantage is that, unlike ISDN, this is an ‘always on’ connection.

SDSL - Symmetric Digital Subscriber Line
SDSL supports symmetric (equal downstream and upstream) data transmissions up to 1.54 mbps.

VDSL - Very High Bit-rate Digital Subscriber Line
VDSL is the fastest of all xDSL flavors and provides transmission rates of 13–52 Mbps downstream and 1.5–2.3 Mbps upstream over a single copper-pair wire, at a distance of 1,000–4,500 feet from the service provider’s premises.