Re: LF: A 9600 bps Note!


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Re: LF: A 9600 bps Note!



At 09:54 AM 11/24/96 GMT, you wrote:
>
>A serial port can run at 115200+ bps if you've got a reasonable UART.  Your
>modem can send information through your serial port at that rate; it
>cannot, however communicate over a phone line at that speed.  I believe
>that 2400 baud is the actual figure you meant.  2400 baud refers to signals
>per second.  The implication is that to communicate above 2400 baud, you
>need to have a range of signals (frequencies) to compensate.  For example,
>you would need 12 different signals in the case of a 28800 bps modem.  The
>problem is that line noise and degradation make it hard to correctly
>differentiate between signals, and this is why modems seem to be slow in
>gaining speed lately.  Data compression just allows the effective data
>transfer rate to be higher than the modem speed in some cases, and this is
>why it is advantageous to have your serial port run at a high rate like the
>aforementioned 115200 in order to accept the decompressed data from the
>modem.
>
>This is a gross simplification, but...
>
>-Kevin
>khuber@mr.net
>
>Ciebiera@aol.com writes:
> > I don't think that anyone's aware that all modems communicate at 9600 baud,
> > that is the fastest a serial port can go the only difference between a
14,400
> > and a 28,800 is the algorythem for the data compression.  If there was a way
> > to emulate that in a new graph link then you could hook up with the internet
> > at 28.8K.  Just thought I'd let everyone know.
>
this is not necissarly directed at you but I think people need to learn how
modems work....


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