Skillnad på ADSL och VDSL

Läs här:

http://www.dslforum.org/aboutdsl/vdsl_tutorial.html

Rent praktiskt innebar VDSL hogre hastighet, bade upstream och downstream.
Pa lite mera teknisk niva ar de ganska lika - VDSL har storre frekvensband bl.a., men moduleringen ar samma (DMT).

"VDSL has an odd technical resemblance to ADSL. VDSL achieves data rates nearly ten times greater than ADSL, but ADSL is the more complex transmission technology, in large part because ADSL must contend with much larger dynamic ranges than VDSL. However, the two are essentially cut from the same cloth. ADSL employs advanced transmission techniques and forward error correction to realize data rates from 1.5 to 9 Mbps over twisted-pair ranging to 18,000 feet; VDSL employs the same advanced transmission techniques and forward error correction to realize data rates from 13 to 55 Mbps over twisted pair ranging to 4500 feet. Indeed, the two can be considered a continuum, a set of transmission tools that delivers about as much data as theoretically possible over varying distances of existing telephone wiring.

VDSL is clearly a technology suitable for a full service network (assuming "full service" does not imply more than two HDTV channels over the highest rate VDSL). It is equally clear that telephone companies cannot deploy ONUs overnight, even if all the technology were available. ADSL may be not a "full service network" technology, but it has the singular advantage of offering service over lines that exist today, and ADSL products are closer in time than VDSL. Many new services being contemplated today can be delivered at speeds at or below T1/E1 rates -- video conferencing, Internet access, video on demand, remote LAN access. For such services, ADSL/VDSL provides an ideal combination for network evolution. On the longest lines, ADSL delivers a single channel. As line length shrinks, either from natural proximity to a central office or deployment of fiber-based access nodes, ADSL and VDSL simply offer more channels, and capacity for services that require rates above T1/E1 (such as digital live television or virtual CD-ROM access)."

Saxat från: http://www.dslforum.org/aboutdsl/vdsl_tutorial.html