Type Analog Support
Downstream
Bandwidth Upstream Bandwidth Range
ADSL Yes Up to 9Mbps Up to 640Kbps Up to 18,000 feet
G.lite Yes Up to 1.5Mbps Up to 512Kbps Up to 18,000 feet
HDSL No 1.544Mbps 1.544Mbps Up to 12,000 feet
SDSL No 1.544Mbps 1.544Mbps Up to 10,000 feet
IDSL No 144Kbps 144Kbps Up to 45,000 feet
VDSL Yes Up to 52Mbps Up to 2.3Mbps Up to 4,500 feet
NOTE:You might find that different vendors and sources document range and bandwidth
figures that are not the same as those in Table 27.1. We have used the Cisco
figures, which are sometimes over or under the values included in other specifications.
The variances should not have a significant impact on the test or real-world
deployment—for example, HDSL might have a range of 15,000 feet or 12,000 maximum,
but wire condition, interference, and other factors can greatly influence this,
and a real-world installation might operate correctly at only 7,000 feet. This chapter
covers only DSL basics consistent with the examination.