FAQ:: DSL 2 You might wonder, if distance is a limitation for DSL, why it's not also a limitation for voice telephone calls. The answer lies in small amplifiers called loading coils that the telephone company uses to boost voice signals. Unfortunately, these loading coils are incompatible with ADSL signals, so a voice coil in the loop between your telephone and the telephone company's central office will disqualify you from receiving ADSL. Other factors that might disqualify you from receiving ADSL include:

• Bridge taps - These are extensions, between you and the central office, that extend service to other customers. While you wouldn't notice these bridge taps in normal phone service, they may take the total length of the circuit beyond the distance limits of the service provider.
• Fiber-optic cables - ADSL signals can't pass through the conversion from analog to digital and back to analog that occurs if a portion of your telephone circuit comes through fiber-optic cables.
• Distance - Even if you know where your central office is (don't be surprised if you don't -- the telephone companies don't advertise their locations), looking at a map is no indication of the distance a signal must travel between your house and the telco center.
• Bad Phone Lines - As in dialup connections, DSL can vary depending on the quality of your phone lines and local telco infrastructure.

More information;

How Stuff Woks: DSL

PC World Article about how DSL functions

Aticle from Talk Broadband about DSL with diagrams

If you want specific information or have a question in particular about getting DSL don't hesitate to call our offices at 530.343.6777.