What is ADSL?

The "A" in ADSL means "asymmetric" DSL. This recognizes that for home users that tend to be consumers rather than data producers, a slower upstream (upload) speed can traded off for a faster downstream (download) speed. In addition, the ADSL standard allows for regular phone service to be squeezed into the low end of the frequency spectrum. ADSL therefore needs a splitter to be placed during installation.

Splitters

A splitter is a small device that captures the first 14khz of frequency and splits them off for phone use. The remaining data is passed onto the DSL equipment. The splitter is the first device a DSL line meets when it arrives on the users premises. Splitters are employed when ADSL lines are provisioned. For SDSL, there is no voice band available, so no need for a splitter.