Asymmetric (ADSL) vs. Symmetric (SDSL)

There are two main types of DSL. Symmetric DSL refers to DSL technologies that provide the same bandwidth upstream (sending) and downstream (receiving). Symmetric DSL services provide identical data rates whether you are sending information, like an email, or receiving information, downloading a file or accessing a web site. Asymmetric DSL provides relatively lower rates upstream but higher rates downstream.

Asymmetric Digital Subscriber Line

ADSL is ideal for most homes and small businesses. Most of its two-way or duplex bandwidth is devoted to the downstream direction, sending data to the user. Only a small portion of bandwidth is available for upstream or user-interaction messages. Most broadband data (graphics and multi-media, for example) need lots of downstream bandwidth . At the same time, the average homes or small business DSL generally requires little upstream bandwidth . Using ADSL, up to 8 megabits per second of data can be sent downstream and up to 640 Kbps upstream. The high downstream bandwidth means that your telephone line will be able to bring motion video, audio, and 3-D images to your home or offices. In addition, a small portion of the downstream bandwidth can be devoted to voice rather data, and you can hold phone conversations without requiring a separate line.

Symmetric Digital Subscriber Line

SDSL is generally used for wideband digital transmission within a corporate site and between the telephone company and a customer. The main characteristic of SDSL is that it is balanced: an equal amount of bandwidth is available in both directions and the data rate is the same in both directions. SDSL can carry as much on a single wire of twisted-pair cable as a T1 line (up to 2 Mbps) but over a somewhat longer range.

So which should I use?

In the majority of cases, ADSL is the cheaper and more appropriate option.
If you don't already know what you want, then ADSL is probably what you're looking for.
If you are still unsure and would like to discuss it, you can contact us on +44 (0)845 862 0070, or email us at sales@goscomb.co.uk.