Hi, Sam,
ADSL is one of the several flavors of xDSL.
DSL = Digital Subscriber Line, a way of delivering
both High-Speed internet data transmission and
POTS (Plain Old Telephone Service) over ordinary
copper wire pairs.
ADSL = Asymmetric DSL
(downstream [to you] faster than upstream)
HDSL = High-bit rate DSL
(1.5MB symmetrical data rate, 2 or 3 wire pairs)
IDSL = ISDN DSL
(DSL over ISDN type line, expensive, moderate speed)
RADSL = Rate Adaptive ADSL
(adjusts to line capabilities)
SDSL = Single line DSL
(one wire pair, high speed symmetrical)
VDSL = Very High Speed DSL
(twisted pair/fiber optic -- HDTV quality)
VADSL = Very High Speed Asymmetric DSL
(subset of VDSL, way faster than ADSL)
Of these, ADSL is the cheapest to implement, as it allows
the greatest number of subscribers for a given aggregate
bandwidth. This is typically a "phone company" last-mile
solution, cuz it's shipped over their wire.
Cable companies use common broadband-style network
cabling (very like your cable TV service uses) to accomplish
essentially the same thing.
In general, the only differences are the device choices,
networking topology, and any silly connection rituals
enforced by the provider.
Our cable provider (Cox) uses an all-NT network to provide
subscriber-side connections, and this has reliability problems
(which they meet with serious server redundancy). Their
service is up most of the time (you couldn't host a serious
server on it, but from a client perspective it's really good).
Our ADSL provider (US West) uses various Unix/Linux flavors,
which delivers much greater native reliability, but then they
screw it up with procedural stuff, and a special "dial-up" driver
(which YOU have to load on YOUR computer) which kicks you
off after either 2 hours of use, or 20 minutes of idle (so they can
recover the IP address for re-use). BUT -- for more money,
of course -- they do have a "deluxe" version of their service
that's "always on" but this is not available to us currently as
they "need to add capacity" to handle the load.
**Note**
The whole idea of "dial-up" on what is actually just
a network is some jerk's bright idea to increase revenues,
and isn't needed AT ALL. The guys I knew who took part in
the DSL pilot program were all shocked and horrified when,
at the end of the pilot, a technician showed up and installed
the "dial-up" driver so they could continue to use the service!
The net result is that, as little as I like the Cox (cable modem)
model, their actual reliability is better, and the service they
provide is more usable. This is true for where I live in my tiny
part of Greater Phoenix, your mileage may vary.
They're both broadband. They're both tons faster than dial-up.
And somewhere in this, I actually answered the question!
All the best,
~~Garry
----- Original Message -----
"Samuel W. Heywood" <[EMAIL PROTECTED]> wrote:
> I also would like to know more about this thing.
<snip>
> What is ADSL?
>
> Regards,
> Sam Heywood
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