🚀 go-pugleaf

In article <19960611.233455.39@axis.demon.co.uk>,
          ncw@axis.demon.co.uk (Nick Craig-Wood) wrote:

> 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(!)

Now, if you find patterns in the noise, you could say that it is no longer
noise! 
... of course, that's what Nick talks about below...

> 
> 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).

Now that's clever... if someone can pull it off

 ... might call it ISDN for hackers!

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

  .. unless the telcos take them over!
                 -Rob.

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