Uh oh, I have seen some comments posted recently about connection speed
and 'modem speed' and I get a feeling that there is a lot of
misunderstanding about modems, speed, bps, rates, frequency (what is
that???), et cetera.

So, me being my long-winded self, I thought I'd add my two cents worth
to see if we can end the confusion. Just remember that the problem
started a long time ago with modem manufacturers and a wonderful
gentleman, named Mr. Baudot, who really had no part in creating the
confusion.

A long time ago, modems were listed as having a SPEED rating of 110 bps,
300bps, 2400bps.  It was because they were capable of transmiting that
many 'bits per second' (bps) that having a 300 baud modem would transmit
300 bits per second and people started to think that baud (the rate of
transmission of data) was directly associated with the amount of data
that could be transmitted per second (bps or bits per second) and was
the 'speed' of a modem.

This concept was thrown into a tizzy (ended up causing mass confusion)
with the advent of the multiplex-modulated format 2400 baud modems.

First, let me pose a question or two. When you dial into your Internet
and you 'hear' the modems talking to each other, isn't your 56k modem
(and that should be a lowercase k, not an upper case K) audible? (you
can hear its transmission and reception?) What is the human voice
range?  Can you 'hear' a frequency of 20,000 Hertz?  How about 50,000
Hz?  Did you know telephone lines are limited to allowing signals
between 300 to 3000 Hertz to pass without any problems while anything
below or above those values are attenuated (blocked)?  So how can a
56,000 speed modem work?

Whether you know it or not, modems still transmit their data with a
frequency range of 300 to 3000 Hz (which is why you CAN HEAR the modems
talking to each other - that is within normal hearing range).  That is
because ordinary phone lines will attenuate signals below or above that
frequency. (Before special radio links were available, if a radio
station wanted to do a remote broadcast from a location, they have to
contract with the phone company to install a special, hi-fidelity,
balanced line that would allow the transmission of signals from 30 Hz to
10,000 Hz.  Without that special line, the remote broadcast would sound
lifeless because of the restricted sound limits.)

So with the advent of the 2400 baud modem, manufacturers discovered a
way to increase the amount of data that could be transmitted per second
while still keeping the 'speed' of the modem within the acceptable
limits of the phone company's lines.  If you divide 9600 by 2400, you
get 4; 14400 yields 6; 28.8k yields 12 and 33.6k yields 14. These all
represent several accepted methods that were implemented to allow more
data to be transmitted per second while still keeping the frequency
range of the modem to 300 to 3000 Hz range. Now the 56k modem does not
fall into this easily divisible format because of the unique algorithms
each manufacturer developed, but the frequency transmission of the modem
still is within the 300 - 3000 Hz range, too.

So there is really no such thing as a 9600 baud modem, it is a 9600 bps
modem.  Same thing is true for a 14.4k, 28.8k, 33.6k and 56k. They are
all operating between 300 to 3000 Hz, but they are modulated in such a
way that they can transmit up to 56,000 bits of information per second.

Now, to throw another wrench into this mess, the FCC 'limits the
transmission speed to 53k'.  We have all seen this in fine print on
modem boxes. Notice that they say speed, not frequency. They sould
actually say 'bps' to eliminate confusion, but you all know about
marketing hype, right?

Why such a big deal about speed? Well, when you drive a car, you look at
the dash and see 60 mph (miles per hour) or kph (kilometers per hour).
Now if there were four people in the car and each was carrying a letter
with information on it to give to a recipient at the destination, you
would not tell someone that your messages are traveling at the rate of
2400 mph (kph), would you?  Just because there are four letter carriers
in the car does not increase the 'speed' at which the messages are
traveling at.  I does indicate the 'amount' of data that you are
sending, and that is the BIG difference.

Therefore, _SPEED_ should NEVER be used to discuss modems, because it
leads to a true misunderstanding of the operation of sending data.  If
there is anything that can and should be used, it is 'bps' (note that it
is all lowercase letters).

Further:
?So what is this 115,000 all about in modem setup screens?

Well, the ordinary dial-up modems we commonly know, by themselves,
cannot transmit at those speeds. That number represents the maximum bps
rate of the computer to the modem (which I believe will soon be changing
to 230,000 with the next generation of communications chips and
motherboards). The modem will take that data and place it into a buffer,
then according to an algorithm in its software, it will compact that
data (think of zip) and then modulate a set of frequencies within the
range of 300 to 3000 Hz with that compacted data. The modulated tones
are then transmitted out to the receiving modem who must demodulate the
tones and extract the compacted data bits back to their original form.
(Remember the problems with the two different 56k modems on the market?
They were incompatible with each other because they did not use the same
methods to compact, modulate and extract the frequencies!!!!!!)

So what does all of this mean to you, the ordinary computer person?

The next time you hear 'speed' used to identify a modem it IS the same
thing as 'bps'.  There is no difference.   However, there is a
difference in 'rates of transmission' between a computer and a modem,
modem to a modem, and modem to a computer, and computer to a
computer!!!!!!  But do not confuse speed with baud or frequency.  I have
heard many 'educated' people say they have a modem that runs at 56k, and
they think that is the frequency that their data is being transmitted
at.  It is the _RATE_ (or the amount of data) their modem is
transmitting per second.

So the next time you all read something in the icon tray that says
xxxxxk (and remember, 'k' is the International Standard abbreviation for
'kilo' which means 1,000.  There is no 'K' in the International
Standards system so whoever wrote that software or designed the
advertisement to display a 'K' was uninformed) or that your download is
occurring at xxxxk, they all are referring to the amount of data flow
per second, commonly called bps (bits per second).  It is a matter of
understanding at which point in the chain the software is giving you
that information that you can use it efficiently.

If we all can stop using the term 'speed' when talking about a modem, we
will all be better off with understanding what is going on.
--
Jean Bourvic :>))

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