My dial-up modem fantasy

My dial-up modem fantasy
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Subject Author Date
My dial-up modem fantasy Green Xenon [Radium] 05-21-2008
Posted by henry cabot henhouse III on May 27, 2008, 9:45 pm
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300 bps ought ta be enuff for neone...





>>>> If it were possible for such PSK to exist, what would be the
>>>> disadvantages of it?
>>>
>>> Hmmm...let me think. Since its not possible to exist, its a moot point
>>> in discussing any advantages or disadvantages
>>
>>
>>Let's say it was possible to exist. What would be the drawbacks?
>
> The laws of physics would have changed, so the universe as we know it
> would cease to exist. Other than that, seems OK to me.
>
>
>



Pure Networks
Posted by Nico Kadel-Garcia on May 24, 2008, 4:47 am
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> Hi:
>
> My internet-access fantasy involves dial-up modem telecommunications
> technology devices which use PSK [Phase Shift Keying] as the modulation
> scheme. This too-good-to-be-true PSK uses only 1-symbol-per-second but
> with a Graham's-number amount of bits-per-symbol.
>
> http://en.wikipedia.org/wiki/Graham's_number
>
> Now that is a lot of bits-per-baud!
>
> If it were possible for such PSK to exist, what would be the
> disadvantages of it?
>
> Thanks,
>
> Radium

I think there's no point. The limited data resolution available to
both older, analog phone lines and contemporary, digital phone lines
sets a hard, hard limit on the available bandwidth for *ANYTHING*
going over a phone line, and contemporary modems are already very
close to that theoreticallimit. So switching people over to a new and
entirely incompatible modem technology would provide no significant
benefit.

Posted by Green Xenon [Radium] on June 5, 2008, 2:16 am
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Nico Kadel-Garcia wrote:


>> Hi:
>>
>> My internet-access fantasy involves dial-up modem telecommunications
>> technology devices which use PSK [Phase Shift Keying] as the modulation
>> scheme. This too-good-to-be-true PSK uses only 1-symbol-per-second but
>> with a Graham's-number amount of bits-per-symbol.
>>
>> http://en.wikipedia.org/wiki/Graham's_number
>>
>> Now that is a lot of bits-per-baud!
>>
>> If it were possible for such PSK to exist, what would be the
>> disadvantages of it?
>>
>> Thanks,
>>
>> Radium
>


> I think there's no point. The limited data resolution available to
> both older, analog phone lines and contemporary, digital phone lines
> sets a hard, hard limit on the available bandwidth for *ANYTHING*
> going over a phone line, and contemporary modems are already very
> close to that theoreticallimit. So switching people over to a new and
> entirely incompatible modem technology would provide no significant
> benefit.


You're talking about bandwidth. A baud of 1-symbol-per-second uses only
a small amount of bandwidth, regardless of the amount of
bits-per-symbol. Right?

Posted by DTC on June 5, 2008, 2:38 pm
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Green Xenon [Radium] wrote:
> You're talking about bandwidth. A baud of 1-symbol-per-second uses only
> a small amount of bandwidth, regardless of the amount of
> bits-per-symbol. Right?

Wrong, but then trying to explain Shannon's Law to you would be a
waste of bandwidth.

Aww...what the heck. I'll feed the troll.

Use of the word baud is outdated as it can't adequately reflect the
additional data load achieved by advanced modulation techniques.

Technically speaking, 900 baud is the highest a standard "toll-quality"
phone line will support. So how did they get 2400 baud modems to work?
They didn't, they got 2400 bps modems to work. A 2400 bps modem is
actually a 600 baud device; but using phase modulation, they got four
different states per baud.

Do you really spend that much time on the john reading Popular Science?

Posted by Green Xenon [Radium] on June 5, 2008, 5:55 pm
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DTC wrote:


> Use of the word baud is outdated as it can't adequately reflect the
> additional data load achieved by advanced modulation techniques.
>
> Technically speaking, 900 baud is the highest a standard "toll-quality"
> phone line will support. So how did they get 2400 baud modems to work?
> They didn't, they got 2400 bps modems to work. A 2400 bps modem is
> actually a 600 baud device; but using phase modulation, they got four
> different states per baud.


I know that.

Baud and bits-per-baud are two different things.

The only way the bit-rate is the same as the baud is if you have 1 bit
per symbol. The 2400 bps using a 600 baud is derived using 4 bits per
symbol. 6X4=24.

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