Subject:
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Re: A Generic Idea
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Newsgroups:
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lugnet.robotics
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Date:
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Sun, 5 Jan 2003 14:45:33 GMT
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Original-From:
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Jim Choate <RAVAGE@EINSTEIN.SSZ.COMspamcake>
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Viewed:
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708 times
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On Sun, 5 Jan 2003, Steve Baker wrote:
> The telephone system can (at best) transmit at 56Kbaud (that's the speed
> of the fastest possible PC modem).
There's a caveat you miss, it is limited using the forms of modulation
that modems use (ie FSK derived). For example ISDN uses a different sort
of modulation (ie Q-modulation) and it does 128k over the same phone
lines. I use ISDN to connect my home site (where I am typing this email on
a Linux box) to connect to my T1 site. That T1 uses the same wire (though
it has distance limits much more constrained than ISDN) bundle to get out
to the rest of the world as the ISDN uses to get into the site. It uses
yet a third sort of modulation yet does up to 1.45 Mb/s.
The -real- caveat with all these is the -distance- to the switch where it
all gets turned into digital data. -That- is what limits the modulation
speeds - noise.
W/ regard to this whole discussion of 2-way wireless and Lego; use either
900MHz (AMD makes a chip that will do 1.45 Mb/s here, or 802.11x.
--
____________________________________________________________________
We are all interested in the future for that is where you and I
are going to spend the rest of our lives.
Criswell, "Plan 9 from Outer Space"
ravage@ssz.com jchoate@open-forge.org
www.ssz.com www.open-forge.org
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Message has 1 Reply:
 | | Re: A Generic Idea
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| (...) Yes - but when they install ISDN or DSL on your line, they switch out some electronics at the telephone exchange - remove some line filtering, pull out the digital part of the stream from the analog part, etc, etc. If you just have the audio (...) (21 years ago, 5-Jan-03, to lugnet.robotics)
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Message is in Reply To:
| | Re: A Generic Idea
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| Nick Tarleton wrote: > I don't know how fast the speaker can change frequency > or how soon it can be reacted to, so I can't get a bandwidth estimate. The telephone system can (at best) transmit at 56Kbaud (that's the speed of the fastest possible (...) (21 years ago, 5-Jan-03, to lugnet.robotics)
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