Re: Demon login using IIDual

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#217

From: Nick Craig-Wood
Date: Tue, 11 Jun 1996 00:00

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Ben Formesyn (formesbc@boat.bt.com) wrote:

> IIR the theoretical limit is around 38000bps, limited by the SNR of the 
> connection and the bandwidth of the connection. Shannon's Theorum has all the 
> gory details if you're really interested(!)

This is correct for a line of a given signal to noise ratio.  However an
analogue telephone line is immediately digitised at the exchange to 64k
(8000 samples per second to 8 bits logarithmic).

If you were very clever and could get in sync with the digitisers (maybe by
looking at artifacts on the incoming channel) then you could certainly do
better than 38k, say 56k (storing 7 bits in each 8 bit sample).

Just an idea, but I bet lots of very clever modem manufacturers are working
on something similar :-)

-- 
|- Nick Craig-Wood ---------------------------------- ncw@axis.demon.co.uk -|
|---- Keep those cards and letters coming, and please don't call again -----|

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From: ncw@axis.demon.co.uk (Nick Craig-Wood)
Subject: Re: Demon login using IIDual
Date: 1996/06/11
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