Wired telephone bandwidth

Robert Baer wrote:
Fred Abse wrote:
On Thu, 04 Mar 2010 00:52:56 -0800, Robert Baer wrote:

But (some??) telcos have deliberately, in some unknown manner,
throttled that so the best one can now do is 28.8Kbaud.

Probably down to SNR (Shannon again).
* Sorry; they tested the line and said noise free, so noise is not the
limiting factor.

They are doing the US equivalent of DACSing to share your line because
you are an unprofitable cheapskate is standard practice.

And the response from then as well as from PUCs is "all we are
required to support is VOICE QUALITY".

All they were ever required to support.

* Not the point; they supported 48+Kbps for ages (20+ YEARS) and all of

56kFlex modems were only around since late 90's and only really stable
and interoperable with ISP kit after the V90 standardisation ~1998.

a sudden crapped it down to 28.8K ON PURPOSE to get dial-up users to get
pissed off enough to $pend more $$$$$$$$ for their DSL (which BTW is
LESS reliable).

RTFM and force your modem to do a V34+ 33k6 connection in old world
technology and you should be able to make the best of a bad job. Or
switch to ISDN then they have to give you real copper or better for that.

ADSL is rock solid in most of the civilised world.

Robert Baer <robertbaer_at_localnet.com> wrote in
news:MY2dnS5_esNSRA3WnZ2dnUVZ_hCdnZ2d_at_posted.localnet:

Joel Koltner wrote:
"MakeNoAttemptToAdjustYourSet"
DoNotAttemptToAdjustYourSet_at_anytime.org> wrote in message
news:8h21p59cn8jfovss79anlslb0s3kei9qv5_at_4ax.com...
NO, IDIOT. It was "handshaking" at that rate. You NEVER got file
transfers at that rate. Not even today. I WILL BET! FOAD!

I used to get ~4.5kB/s downloads with the modem reporting connecting
speeds to 46-52kbps similar to what Keith reported. It wasn't twice
the speed of 28.8kbps modems, but *very* noticeably faster.


Wish Qwest would go back to that...


my downloads thru Opera 9.64 are usually around 5.3 Kbps.
at first read,it goes as high as 12Kbps,but rapidly decays to ~5K.
I figure it's the browser overhead that makes the difference.

basic rate of the connection

MakeNoAttemptToAdjustYourSet wrote:
On Thu, 04 Mar 2010 22:52:44 -0600, "k...@att.bizzzzzzzzzzzz"
k...@att.bizzzzzzzzzzzz> wrote:

On Thu, 04 Mar 2010 20:39:49 -0800, MakeNoAttemptToAdjustYourSet
DoNotAttemptToAdjustYour...@anytime.org> wrote:

On Thu, 04 Mar 2010 18:05:02 -0600, "k...@att.bizzzzzzzzzzzz"
k...@att.bizzzzzzzzzzzz> wrote:

Wrong, AlwaysWrong.  When v.90 modems first came out I was regularly doing
48-52K on one of my POTS lines (the other was stuck at 28.8 because it went
five miles, all the way back to the CO).

NO, IDIOT. It was "handshaking" at that rate.  You NEVER got file
transfers at that rate.  Not even today.  I WILL BET!  FOAD!
Wrong, as always.

 Try it with ANY 10MB file, and the numbers and the transfer do not
match.  and don't even try to hand me a load of horseshit about packet
headers, you retarded little piece of DUMB motherfucker shit.  The Speeds
were NEVER attained, and I was right next door to the goddamned switch
with top gear online, fuckhead!

But clearly without any clue how to make it work correctly.

Wrong, as always.

Not to mention that I actually researched it, and I happen to remember
what I learned.  You have obviously forgotten.  If you ever knew.
Obviously wrong, as always.

Give it up, AlwaysWrong.  You'll *always* be wrong.  It's just you..

 Said the utter retard that actually thinks he ever got files over POTS
at 52 kbits per second.

Look in the mirror. KRW is absolutely right about this. The download
speed of the 56k technology is substantially faster than V34+.

I was involved in benchmarking it when the original 56k technology was
under test. There were problems establishing a good connection early on.

But a nominal 48000 56kFlex connection was good for download speeds
5.2kb/s of ZIP file or 9kb/s of news and the rival V90 spec at 48000
gave 5.3kb/s for ZIP and nearly 10kb/s for news on the same hardware.

ISTR the US system robs some of the bandwidth 1/8th? for private
signalling so the numbers in the USA will not be quite so good.

A set of suitable test files for tuning dialup connections is still on
the Demon ftp server if you want to check. Time to download "Fullfile"
will give a very good indication of your raw connection speed. It is
designed to be incompressible even with the best algorithms.

ftp://ftp.demon.co.uk/pub/test/

The highest speed download you can have is the emptyfile which is
extremely compressible and tests the serial interface handshaking.
Certain common misconfigurations show with it. You need an internal
modem or a 230kbaud serial interface to keep up with the datapump.

V34+ could manage 3.7kb/s for ZIP and 7k/s for news on the same line.
And V34+ was always preferable on a shared DACS line where the available
bandwidth was heavily compromised by distortion.

Obviously if you have the option then ADSL or ISDN is better still.

Regards,
Martin Brown- Hide quoted text -

- Show quoted text -

On Fri, 05 Mar 2010 16:12:00 +0000, Martin Brown
|||newspam|||@nezumi.demon.co.uk> wrote:

basic rate of the connection


A number no one here seems to know or understand.

On Mar 5, 3:38 am, Martin Brown <|||newspam...@nezumi.demon.co.uk
wrote:
MakeNoAttemptToAdjustYourSet wrote:
On Thu, 04 Mar 2010 22:52:44 -0600, "k...@att.bizzzzzzzzzzzz"
k...@att.bizzzzzzzzzzzz> wrote:

On Thu, 04 Mar 2010 20:39:49 -0800, MakeNoAttemptToAdjustYourSet
DoNotAttemptToAdjustYour...@anytime.org> wrote:

On Thu, 04 Mar 2010 18:05:02 -0600, "k...@att.bizzzzzzzzzzzz"
k...@att.bizzzzzzzzzzzz> wrote:

Wrong, AlwaysWrong.  When v.90 modems first came out I was regularly doing
48-52K on one of my POTS lines (the other was stuck at 28.8 because it went
five miles, all the way back to the CO).

NO, IDIOT. It was "handshaking" at that rate.  You NEVER got file
transfers at that rate.  Not even today.  I WILL BET!  FOAD!
Wrong, as always.

 Try it with ANY 10MB file, and the numbers and the transfer do not
match.  and don't even try to hand me a load of horseshit about packet
headers, you retarded little piece of DUMB motherfucker shit.  The Speeds
were NEVER attained, and I was right next door to the goddamned switch
with top gear online, fuckhead!

But clearly without any clue how to make it work correctly.

Wrong, as always.

Not to mention that I actually researched it, and I happen to remember
what I learned.  You have obviously forgotten.  If you ever knew.
Obviously wrong, as always.

Give it up, AlwaysWrong.  You'll *always* be wrong.  It's just you.

 Said the utter retard that actually thinks he ever got files over POTS
at 52 kbits per second.

Look in the mirror. KRW is absolutely right about this. The download
speed of the 56k technology is substantially faster than V34+.

I was involved in benchmarking it when the original 56k technology was
under test. There were problems establishing a good connection early on.

But a nominal 48000 56kFlex connection was good for download speeds
5.2kb/s of ZIP file or 9kb/s of news and the rival V90 spec at 48000
gave 5.3kb/s for ZIP and nearly 10kb/s for news on the same hardware.

ISTR the US system robs some of the bandwidth 1/8th? for private
signalling so the numbers in the USA will not be quite so good.

A set of suitable test files for tuning dialup connections is still on
the Demon ftp server if you want to check. Time to download "Fullfile"
will give a very good indication of your raw connection speed. It is
designed to be incompressible even with the best algorithms.

ftp://ftp.demon.co.uk/pub/test/

The highest speed download you can have is the emptyfile which is
extremely compressible and tests the serial interface handshaking.
Certain common misconfigurations show with it. You need an internal
modem or a 230kbaud serial interface to keep up with the datapump.

V34+ could manage 3.7kb/s for ZIP and 7k/s for news on the same line.
And V34+ was always preferable on a shared DACS line where the available
bandwidth was heavily compromised by distortion.

Obviously if you have the option then ADSL or ISDN is better still.

Regards,
Martin Brown- Hide quoted text -

- Show quoted text -

Last I checked, ISDN was VERY EXPENSIVE, if you could even still get
it.
For the price, you would almost certainly go with DSL or cable, maybe
even wireless (if that's an option where the OP is?)

On Thu, 04 Mar 2010 06:39:17 -0600, Jim Yanik <jyanik_at_abuse.gov
wrote:

I'm still on dialup,and I usually log on at 48K,according to the W98SE
taskbar indicator.Sometimes,it logs on at 49K,but it's never stable.
ISTR that the max limit was 52K,but was usually limited by coils in the
lines.

At least in Europe, the "56k" only worked in the downlink direction,
i.e. the ISP had a typically a E1 (2.048 Mbit/s) connection for 30
subscribers and a bit by bit copy at 64 kbit/s 8000 samples/s was
delivered to the DAC in the telephone exchange of the subscriber.

Theoretically, the 8 bits/sample can represent 256 analog values,
since the floating point A-law representations use different step
sizes depending of the "amplitude", the smallest steps are about the
same size as a the LSB of a 12 bit DAC.

The cabling from the local exchange to the subscriber modem will
distort the waveform to the modem and the equalizer in the modem tries
to compensate for the distorted waveform and tries to determine which
actual analog voltage was generated by the DAC. In practice, about
50-100 discrete voltage levels can be reliably detected, thus about
5.5-6.5 bits/sample can be transferred, corresponding to 44-52 kbit/s.

Of course, any noise in the subscriber cable (such as crosstalk from
ADSL connections in other pairs) will degrade the SNR and hence reduce
the throughput.

In the US, the T1 connection and u-law compression may have different
constraints. Are they still using in-band signaling ? This at least
caused a lot of problems in early ISDN and pre-ISDN connections across
the Pond.

If the telco would deliberate want to force the use of 28k even on
downlink, then they either would have to add some LSB noise to the
samples, but only when the sample "amplitude" is low, which would
appear as a slightly added noise in a voice contact. Alternatively,
some analog noise would have to be added after each DAC in each
telephone exchange.

AFAIK that is the way it is supposed to work here in the US.

Paul Keinanen wrote:
On Thu, 04 Mar 2010 06:39:17 -0600, Jim Yanik <jyanik_at_abuse.gov
wrote:

I'm still on dialup,and I usually log on at 48K,according to the W98SE
taskbar indicator.Sometimes,it logs on at 49K,but it's never stable.
ISTR that the max limit was 52K,but was usually limited by coils in the
lines.

At least in Europe, the "56k" only worked in the downlink direction,
i.e. the ISP had a typically a E1 (2.048 Mbit/s) connection for 30
subscribers and a bit by bit copy at 64 kbit/s 8000 samples/s was
delivered to the DAC in the telephone exchange of the subscriber.

Theoretically, the 8 bits/sample can represent 256 analog values,
since the floating point A-law representations use different step
sizes depending of the "amplitude", the smallest steps are about the
same size as a the LSB of a 12 bit DAC.

The cabling from the local exchange to the subscriber modem will
distort the waveform to the modem and the equalizer in the modem tries
to compensate for the distorted waveform and tries to determine which
actual analog voltage was generated by the DAC. In practice, about
50-100 discrete voltage levels can be reliably detected, thus about
5.5-6.5 bits/sample can be transferred, corresponding to 44-52 kbit/s.

Of course, any noise in the subscriber cable (such as crosstalk from
ADSL connections in other pairs) will degrade the SNR and hence reduce
the throughput.

In the US, the T1 connection and u-law compression may have different
constraints. Are they still using in-band signaling ? This at least
caused a lot of problems in early ISDN and pre-ISDN connections across
the Pond.

If the telco would deliberate want to force the use of 28k even on
downlink, then they either would have to add some LSB noise to the
samples, but only when the sample "amplitude" is low, which would
appear as a slightly added noise in a voice contact. Alternatively,
some analog noise would have to be added after each DAC in each
telephone exchange.

AFAIK that is the way it is supposed to work here in the US.

On Fri, 05 Mar 2010 10:41:10 +0000, Martin Brown
|||newspam|||@nezumi.demon.co.uk> wrote:

Robert Baer wrote:
Fred Abse wrote:
On Thu, 04 Mar 2010 00:52:56 -0800, Robert Baer wrote:
But (some??) telcos have deliberately, in some unknown manner,
throttled that so the best one can now do is 28.8Kbaud.
Probably down to SNR (Shannon again).
* Sorry; they tested the line and said noise free, so noise is not the
limiting factor.
They are doing the US equivalent of DACSing to share your line because
you are an unprofitable cheapskate is standard practice.

You've probably hit the nail squarely here. The various methods are
collectively known as "pair gain", on this side of the pond.

And the response from then as well as from PUCs is "all we are
required to support is VOICE QUALITY".
All they were ever required to support.
* Not the point; they supported 48+Kbps for ages (20+ YEARS) and all of
56kFlex modems were only around since late 90's and only really stable
and interoperable with ISP kit after the V90 standardisation ~1998.

X2 and Vflex were usable. I remember choosing ISPs based on which modem banks
they used. I remember when my ISP switched from X2 to Vflex. They denied it
but I gave them the make and series of the old and new modems (I had
development code for my modem that would tell everything about the modem at
the other end). They didn't appreciate being caught in a lie.

a sudden crapped it down to 28.8K ON PURPOSE to get dial-up users to get
pissed off enough to $pend more $$$$$$$$ for their DSL (which BTW is
LESS reliable).
RTFM and force your modem to do a V34+ 33k6 connection in old world
technology and you should be able to make the best of a bad job. Or
switch to ISDN then they have to give you real copper or better for that.

ISDN has always been stupidly expensive in the US. DSL is far cheaper.

ADSL is rock solid in most of the civilised world.

If you're close enough to the DACs. The US is a big place and there is a
*lot* outside the range of DSL.

BozoBin Now Invisible....

sidelight: When I worked as a Broadcast Engineer, I kept trying to use
the POTS for occasional Remote Broadcast purposes.

What Worked:

- On local (not through multiplex systems) exchanges, the actual
bandwidth was about 100 to 5000 Hz. I built couplers on and off the
dialed network that supported that bandwidth and they sounded good.
Built an automatic answerer on a dedicated incoming line and the
prearranged daily "remote studio" calls popped up a light on the
control board, and the DJ could use the regular "remote talkback"
switch to talk to them and confirm. The remote users then heard "Cue
audio" of the station until they heard their cue, the switch went from
CUE to LIVE and they were on the air.

- On long-distance calls, the same system was used but it was obvious
the bandwidth was limited. The most obvious result was loss of lows so
the voices were missing their nice quality. But it was OK for Sports
broadcasts.

Since Back Then:

- Some hardware exists which sends the 50-300 Hertz audio as a
subcarrier in the 2500-3000 Hz range. Some loss of "Highs" in the
audio, but the Lows are restored.

- Some broadcast stations used Modems over the POTS to send processed
audio. Worked pretty well.

- These days, of course, remote broadcasts are routinely sent as VOIP
(but sometimes with specific software with better low end and
automatic gain control etc..) Anybody currently in Broadcast?? Please
tell us about the current practices...

DSL was seemingly an Impossible Dream "Back Then"...

I worked on ISDN a bit at IBM. It turned out to fit it's internal
acronym: "I Still Don't Need It"...

krw_at_att.bizzzzzzzzzzzz wrote:
On Fri, 05 Mar 2010 10:41:10 +0000, Martin Brown
|||newspam|||@nezumi.demon.co.uk> wrote:

Robert Baer wrote:
Fred Abse wrote:
On Thu, 04 Mar 2010 00:52:56 -0800, Robert Baer wrote:
But (some??) telcos have deliberately, in some unknown manner,
throttled that so the best one can now do is 28.8Kbaud.
Probably down to SNR (Shannon again).
* Sorry; they tested the line and said noise free, so noise is not the
limiting factor.
They are doing the US equivalent of DACSing to share your line because
you are an unprofitable cheapskate is standard practice.

You've probably hit the nail squarely here. The various methods are
collectively known as "pair gain", on this side of the pond.

Sounds like the same sort of scheme. BT like NASA speaks entirely in
TLAs, ETLAs and SETLAs. DACS stands for Digital Access Carrier System I
think mostly made by Telspec. Is the US pair gain the same technology?

And the response from then as well as from PUCs is "all we are
required to support is VOICE QUALITY".
All they were ever required to support.
* Not the point; they supported 48+Kbps for ages (20+ YEARS) and all of
56kFlex modems were only around since late 90's and only really stable
and interoperable with ISP kit after the V90 standardisation ~1998.

X2 and Vflex were usable. I remember choosing ISPs based on which modem banks
they used. I remember when my ISP switched from X2 to Vflex. They denied it
but I gave them the make and series of the old and new modems (I had
development code for my modem that would tell everything about the modem at
the other end). They didn't appreciate being caught in a lie.

I was an early adopter and involved in the testing of my ISPs server
upgrades. I had automatic logging and statistical analysis of all
connects, EQM and failure codes. Some of it was published in their FAQs
to help others get 56Flex and then later V90 to work reliably.

Certain firmware versions and combinations were very much more reliable
than others. They were interesting times (and like you I had control of
some registers that are no longer user configurable).

a sudden crapped it down to 28.8K ON PURPOSE to get dial-up users to get
pissed off enough to $pend more $$$$$$$$ for their DSL (which BTW is
LESS reliable).
RTFM and force your modem to do a V34+ 33k6 connection in old world
technology and you should be able to make the best of a bad job. Or
switch to ISDN then they have to give you real copper or better for that.

ISDN has always been stupidly expensive in the US. DSL is far cheaper.

ADSL is cheaper here too, but if the local copper won't support it then
ISDN still gives you real 64k raw digital without compression and 128kb
with both channels bonded. UK price is about 2.5x that of an ordinary
phone line and it means you have a pair of adjacent phone numbers for
fax/phone. There was a time when ISDN was ludicrously priced to protect
their incredibly lucrative Kilostream fixed line rentals.

ISDN is good enough to carry almost broadcast quality digital sound.

Even Belgium manages to do ISDN at a sensible price although their ugly
phone connectors look like they are intended to carry 4A mains power!

ADSL is rock solid in most of the civilised world.

If you're close enough to the DACs. The US is a big place and there is a
*lot* outside the range of DSL.

I am nominally at the range limit ~12 miles of ADSL in a rural area but
still get almost 4M connection on old wires buried underground. I'd
hazard a guess that it might work at 1M these days out to 20 miles.

They may be better served by mobile phone data services then. That is
becoming affordable here on USB dongles (eg 1 GB @3Mb/s is £10-12 pcm,
although 3Gb @ upto 7Mb/s for £15 is better value).

ISDN has always been out of the question in the US. The tariff structure has
always been dumb. V.90 put the nail in ISDNs coffin.

They tell us 17K' (3 miles). I'm right at that limit and recently had to
downgrade to 768K (after 1-1/2 years working at 3Mb).