Re: connection speed when using pon
On Monday 31 January 2005 13:06, John Hasler wrote:
>I wrote:
>> But they do not take into consideration the compression done by
>> the modem.
>
>Gene Heskett writes:
>> Oh, but it does.
>
>Those numbers represent the raw bit rate (not baud rate) between the
>modems. The effective data transfer rate can be much higher but
> depends on the compressibility of the data.
>--
>John Hasler
I hate to disapoint you John, but the modems are doing all possible
amounts of compression to achieve the data rates they advertise. The
compressions they use are not the same as the equ of bzip2, and work
in the phase & amplitude domains of the signals exchanged in order to
achieve a 56k download rate on what is, according to bandwidth
theory's carved in stone back in the late 50's by some very smart
people in information theory at bell labs as to the maximum data rate
that can be sent over what is basicly a 2400 hz of bandwidth circuit.
That 56k is the data rate through the most restrictive piece of the
transmission path, the POTS line to the CO, and is what you will get
over any period long enough to calculate an average from, such as any
one 10 second period, measured at the computers side of the modems on
either end.
I believe a fellow named Robert Heinlein said it best when he
popularized the phrase/acronym TANSTAAFL 40 years ago.
--
Cheers, Gene
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by Gene Heskett are:
Copyright 2005 by Maurice Eugene Heskett, all rights reserved.
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