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A T1 line and an SDSL line uses the same underlying technology - HDSL. The differences between them are not in performance, they are in ease of provisioning and speed of repair.


In the US, lines for T1 data are normally treated as higher importance by telcos, than DSL lines, so time to repair and provisioning can be considerably faster. A T1 fault may be repaired within hours, or a day, whereas a DSL line fault could be a 5 day turn around time.


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, compare that with SDSL prices of a few hundred dollars for the same speed.

T1 lines are often provisioned with a service level agreement (SLA) that may include guarantees on the speed, and reliability of the service, maximum time to repair, compensation in the event of an outage, and so on. A 1.5mbit SDSL line will generally come with an SLA that is less favorable to the customer.


Feedback received on this FAQ entry:
  • send me an email at ronaldedwinbyrd@gmail.com and I will send you some pictures and info to add to the FAQ for T1 vs. HDSL. "A T1 line and an SDSL line uses the same underlying technology - HDSL" this is not accurate.

    2011-01-27 11:11:03 (FLengineer See Profile)



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