Dial-up Modem Speed of 56 Mbps?

On 27 Apr 2007 01:44:40 GMT, thanatoid
wrote:


That being said, can we change the name of the thread to "anal-
retentive geeks with nothing to do talk about totally irrelevant
things"... Oh wait... That would pretty much apply to 95% of
Usenet text posts, wouldn't it...


Do you not even have the slighest fathom of why a thread
subject line is to stay UNCHANGED?



As I gently suggested in a previous post, "troll methods" are
just a normal part of human/semi-human communication which some
people with 12 MB hard drives up their asses seem to arbitrarily
have occasional problems with.


Wrong. "Troll methods" are employed by those who have no
useful purpose, who only aim to cause waste or elicit
emotion from others who had a useful goal.



(Speaking of trolls, the REAL troll in this mess, the OP, was
EXTREMELY successful in baiting us to drag this on for this
long. S/he must be peeing his/her pants.)


Then why did you take the bait?

One the very first post by the troll, a trend is set. We
could see instantaneously that there was no purpose. Of
course if one wrote an elaborate enough proxy, all these
modems could be teamed to achive a higher bitrate. Even so,
it would be an incredible waste since broadband exists and
could achieve so much higher with far fewer slave systems.

To concentrate on an unrealistic scenario, the OP began with
an obvious attempt at unfruitful discourse.

kony wrote in
:

On 27 Apr 2007 01:44:40 GMT, thanatoid
wrote:

That being said, can we change the name of the thread to
"anal- retentive geeks with nothing to do talk about
totally irrelevant things"... Oh wait... That would pretty
much apply to 95% of Usenet text posts, wouldn't it...

Do you not even have the slighest fathom of why a thread
subject line is to stay UNCHANGED?

Do you not even have the slightest amount of a sense of humor?
As to changing thread subject names, I believe another
respondent put it rather succinctly... Check again if you
haven't seen it.

As I gently suggested in a previous post, "troll methods"
are just a normal part of human/semi-human communication
which some people with 12 MB hard drives up their asses
seem to arbitrarily have occasional problems with.


Wrong. "Troll methods" are employed by those who have no
useful purpose, who only aim to cause waste or elicit
emotion from others who had a useful goal.

You REALLY should try to get a life.

(Speaking of trolls, the REAL troll in this mess, the OP,
was EXTREMELY successful in baiting us to drag this on for
this long. S/he must be peeing his/her pants.)

Then why did you take the bait?

I have nothing better to do. Yes, *I* have NO life, which
doesn't mean everyone should be like me.

One the very first post by the troll, a trend is set. We
could see instantaneously that there was no purpose. Of
course if one wrote an elaborate enough proxy, all these
modems could be teamed to achive a higher bitrate. Even
so, it would be an incredible waste since broadband exists
and could achieve so much higher with far fewer slave
systems.

To concentrate on an unrealistic scenario, the OP began
with an obvious attempt at unfruitful discourse.

And so the OP keeps on peeing his/her pants...

Next?


--
Disagreements and the usual insults expected and welcomed.

kony wrote:
thanatoid wrote:

That being said, can we change the name of the thread to "anal-
retentive geeks with nothing to do talk about totally irrelevant
things"... Oh wait... That would pretty much apply to 95% of
Usenet text posts, wouldn't it...

Do you not even have the slighest fathom of why a thread
subject line is to stay UNCHANGED?

I firmly disagree. The subject should describe the material. When
the subject changes there is no real reason to maintain access to
older posts, although the reference system will preserve all that.

--
http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.txt
http://www.securityfocus.com/columnists/423
http://www.aaxnet.com/editor/edit043.html
http://kadaitcha.cx/vista/dogsbreakfast/index.html
cbfalconer at maineline dot net



--
Posted via a free Usenet account from http://www.teranews.com

On Fri, 27 Apr 2007 09:18:46 -0400, CBFalconer
wrote:

kony wrote:
thanatoid wrote:

That being said, can we change the name of the thread to "anal-
retentive geeks with nothing to do talk about totally irrelevant
things"... Oh wait... That would pretty much apply to 95% of
Usenet text posts, wouldn't it...

Do you not even have the slighest fathom of why a thread
subject line is to stay UNCHANGED?

I firmly disagree. The subject should describe the material. When
the subject changes there is no real reason to maintain access to
older posts, although the reference system will preserve all that.


If the content of the post was deviating from the original
subject, yes. If it is just a typical thread reply where
the poster replied as everyone else had, but felt they
should edit the subject line to inject some personal opinion
that could have been in the body of the post, no.

On 24 Apr 2007, in the Usenet newsgroup comp.dcom.modems, in article
.com, Radium wrote:


This all assumes you would be bonding connections to a single ISP.
Trying to dial in to multiple ISPs is possible, but requires that
each connection be a separate one - thus the chance of aggregating
bandwidth is nearly nil.

Actually, I was thinking of multiple ISPs. A different ISP for each
line.

OK - think of an IP connection as you having a conversation with some
other person. As long as there is one IP address at each end of
the conversation (bonding), you will see an increase. If there are
instead, one hundred addresses on your end, your peer in this
conversation is going to be EXTREMELY confused. "I'm trying to
talk to you, and all these other people keep butting in to the
conversation." So that ain't gonna work. Have you got a web
page you're trying to load with 100 different images built in? As
long as there are no inter-dependencies (cookies and such) then you
may be able to download them over separate links, but your operating
system is going to go nuts trying to figure out who (which application)
gets what, and I don't know of any operating system and application
such as a browser or proxy server that can handle this.

Yes, each connection can carry independent data - the problem is trying
to consolidate the resulting mess into a coherent picture. If you are
old enough to remember the Applo 11 landing on the moon (or going way
back - the coronation of Queen Elizabeth in 1952) there was very limited
world wide television coverage - the 1952 event took _all_ of the under
sea cable telephone circuits to deliver a crappy picture. We don't do
that any more, because there are better ways (satellite relay). No one
is wasting time trying to do it the old fashioned way.

Old guy

Radium wrote:

Is it possible to obtain a 56 Mbps connection using 1,000 dial-modems
with a 1,000 different telephone ports and numbers?

No, you cant ever even get a 56 connection with a single modem on a
single computer.

--
http://www.bootdisk.com/

"Radium" wrote in message
oups.com...

Dial up modems operate on the same frequency as regular voice
communications on the phone line - between 300 and 3000 Hz. Does this
mean that sounds on the line used by dial-up modem have a maximum
pitch of 3 KHz?


yes. the American system may be 300 to 3400 hz, i'm not sure.

C = 0.332 * B * SNR
C = 0.332 * 3000 * 30
C = 29,880 bits/second

in that approximation, bandwidth and signal to noise ratio are proportional
to capacity.

"T" wrote:
"Radium" wrote in message
roups.com...

Dial up modems operate on the same frequency as regular voice
communications on the phone line - between 300 and 3000 Hz. Does this
mean that sounds on the line used by dial-up modem have a maximum
pitch of 3 KHz?


yes. the American system may be 300 to 3400 hz, i'm not sure.

It is intended to be "at least" 400-2800Hz. That is the
*minimum* specification for a "voice grade" dilaup line. (There
are several different "voice grade" specifications, including
400-2800Hz (dialup), 300-3000Hz (private line), and 300-3400Hz
(PCM link), for different types of equipment.)

However, 1) most lines are significantly better than minimum
specifications, and 2) if there is no way to provide at least a
minimum specified line the telco can legally opt to provide a
below minimum specified line that will actually work well enough
to provide useable voice calls.

Note also that the minimum Signal to Noise Ratio is 24 dB, but
typically would be much better than that.

C = 0.332 * B * SNR
C = 0.332 * 3000 * 30
C = 29,880 bits/second

Shannon's formula is

Capacity = Bandwidth * ( 1 + S/N )

where Capacity is bits per second
Bandwidth is channel bandwidth in Hertz
S is signal power
N is Gaussian noise power (expressed in the same terms as S)

Note that S/N is *not* expressed in terms of decibels.

But if the SNR is significantly greater than 1, the above formula
is approximately correct where B is Hz bandwidth and SNR is expressed
in dB.

And... much more interesting numbers can be plugged in...

A 400-2800Hz channel with a 24 dB SNR,

C = 0.332 * 2400 * 24 = 19,123

Keep that figure in mind for the discussion of v.32bis below.

in that approximation, bandwidth and signal to noise ratio are proportional
to capacity.

Bandwidth of a typical telephone connection varies from a
minimum of 400-2800Hz, up to something approaching 0-4000Hz, or
even greater under some circumstances. Signal to Noise ratios
are specified at 24 dB minimum, but might be as high as 65 dB.

Connections that include any type of digital carrier
transmission system, including digital switching systems, will
have less than 0-4000Hz bandwidth, and an SNR no higher than 37
dB; but on a directly connected wire loop using a typical
mechanical switching system, the bandwidth will be greater (T1
lines require 750KHz, for example.)

Using the approximation of Shannon's formula and the minimum
specification for a PCM link, and assuming the cables connecting
each end add as much noise as the PCM link, we get

C = 0.332 * 3100 * 34 = 34,992

as the absolute best one could ever get through a digital
switched PSTN connection. Which explains why v.34++ only goes
to 33.6Kbps.

For connections that only include some form of analog carrier
transmission system, the bandwidth will almost certainly be
limited to 200-3500Hz at the most, but might have SNR values
greater than 45 dB too.

For connections that include some form of standard 64Kbps PCM
digital carrier, the bandwidth is limited to a maximum of
80-3750Hz, and the SNR will never be more than 37 dB. (For
other digital systems such as any of those using 32 Kbps, the
ranges are lower.)

Hence the actual bandwidth and SNR of any given telephone
connection can vary greatly depending on how the connection is
routed. Modem protocols such as V.34 were designed to take that
into account and provide the best data rates possible for
whatever conditions actually exist on the line. Prior to that
all protocols were designed only to take advantage of a
minimally specified telephone line (hence a v.32bis modem can
obtain a 14.4Kbps rate over a mimimally specified telephone
connection).

A few requirements for various data rates and protocols are,

Rate Protocol Bandwith Frequency_Range
14.4Kbps v.32bis 2400Hz 600-3000Hz
24.0 v.34 2800 467-3267
26.0 v.34 3000 375-3375
28.8 v.34 3200 320-3520
31.2 v.34 3200 359-3559
33.6 v.34 3429 244-3674

V.90 protocols require 3600Hz of bandwidth from
150 to 3750Hz within the following limits,

Less than 10 dB rolloff below 300Hz
Less than 24 dB rolloff above 3450Hz
Less than 43 dB attenuation end to end
No load coils, bridgetaps or wire gauge changes
Only 1 digital to analog conversion (CODEC)

What signficance is there to all of that??? Well, it means that
a typical v.90/v.34 modem makes a *very* good piece of test
equipment to determine the quality of a telephone line! If a
14.4Kbps connection can be established, the line clearly meets
minimum specifications. If it can accomplish any of the higher
v.34 bit rates, it is clearly a very good line. A connection
that allows negociation of any v.90 bit rate is simply an
astounding feat!

And, after all of those numbers for bandwidth... a word of
caution: Shannon was talking about 6 dB bandwidth points, but
the 400-2800Hz minimum spec for a telephone line can have as
much as 14 dB rolloff at either 400 or 2800Hz compared to
1000Hz. So all of the above bandwidth figures are relative.

--
Floyd L. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

"Fred Hess" wrote in
message
news
Have you read any RFCs, ****wit?


feel free to do all the trolling you want, one day you'll wake up and
realize you are a loser and a nobody.