ADSL and modem notion

Hi Guys,

Here is a more complete answer to the wet string question.

Pre DSL telco lines restricted the available bandwidth to 4 Khz. This was an equipment limitation, not a limitation of the phone line.

All phone lines were optimised for Voice not Data, and Voice only needs the first 4 Khz of bandwidth to be usable. This meant all modems could only use 4 Khz of bandwidth for their data transmisson. Any signals above the 4 Khz mark were ignored by the Telco switches as they are optimised for voice not data.

DSL provides a new access network for data, while allowing voice to use the traditional telco network. By providing a new data access network the bandwidth of the phone line can be increases to 1.1 (adsl) or 2.2 Mhz (Adsl2+ / VDSL).

And I do not work for an ISP...I have far more fun building DSL networks for Telcos & ISPs and teaching them how to uses them properly.