What is the difference between T1 and 1.5mbps SDSL?
A T1 line and an SDSL line use the same underlying technology – HDSL. The differences between them are not in performance, but their ease of provisioning and speed of repair. In the United States lines for T1 data are normally treated with higher importance than the DSL lines are by the Telcos therefore the time for repair and provisioning is considerably faster. A T1 fault may be repaired in a day or even within hours whereas a DSL line fault repair could take up to 5 days. The other important difference is that T1 lines are more easily repeated to cover longer distances, something that has not yet happened for SDSL lines. T1 lines are significantly more expensive than DSL lines. A monthly T1 lease, with Internet bandwidth, can amount to $1000 or more, compared with SDSL prices of a few hundred dollars for the same speed.
