No its an ADSL router not SDSL.
They are two different technologies ones asymmetric and ones symetric. The linksys box doesnt support the later.
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 6.1 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 computer or hooked-in TV set. 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 1.544 Mbps) but over a somewhat longer range.