[PLUG] (no subject)

[Russ Johnson]

At 02:24 PM 5/10/2002 -0700, you wrote:
>You can run your own DSL circuit without a DSLAM by getting a dry
>pair (like an alarm circuit) between two locations and putting a
>DSL modem at each end. Bob Cringley described such a setup in one
>of his columns. <http://www.pbs.org/cringely/pulpit/pulpit20010823.html>

I knew this. :)

>Regular modems are sending digital data to each other, too. It's just
>modulated on top of an audio carrier. In fact, that's what "mo-dem"
>is from - modulator/demodulator.

That's the point. There isn't a "carrier" with DSL. It's all signal. And 
digital to boot. What you "hear" when you remove the filter is the signal, 
not a carrier. The DSL "modem" isn't modulating or demodulating. It's 
converting one digital signal (the DSL signal) into another (ethernet 
frames) and vice versa.

>I'm not familiar enough with ethernet to say for certain, but I thought
>ethernet line drivers directly drove the wires with the digital signal,
>rather than encoding it onto a carrier.

It was an example. The original argument seemed to say, "It's on voice 
lines, so it must be analog". I extended this to include the fact that 
voice lines are also (usually) copper.


Russ Johnson
http://www.dimstar.net


Fashion is a form of ugliness so intolerable that we have to alter it
every six months.
                 -- Oscar Wilde