ADSL actually uses what could be referred to as a Radio Frequency carrier with the data modulated on top of it in much the same fashion as is done in a Cable Modem. Now it isn't really surprising that cable can carry broadband signals - cable system regularly carry frequencies from roughly 30 MHz at the low end to 1 GHz plus at the high end. Using some bandwidth in the 100s of MHz range to carry data streams is pretty obvious. What was clever was to allow as single-direction system to carry data in both directions. That is why your Download speed is probably 10X your upload speed (on cable). Now the really bright folks who designed ADSL did something which most of us thought was impossible - they managed to send & receive radio frequency carriers over an ordinary twisted pair POTS line. The little filter unit which you plug into RJ11s where you have telephones blocks the RF from the phone so as not to overload the phone electronics AND also to prevent signal absorption of the RF carrier in the phone circuits. That they made it work is a testament to good engineering, IMHO. Roy J. Gromlich ----- Original Message ----- From: "David P Harris" To: Sent: Tuesday, January 20, 2004 8:15 PM Subject: Re: [EE] Why don't baud rates just double? > Hi- > Well ADSL really uses the bandwidth available that is not the original > telephone bandwidth, i.e. it is broad band with the telephone > frequencies deleted. Still damn clever... > David > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body