LinuxSA Mailing list archives

  From: Leigh Hart <hart@dotat.com>
  To  : David Lloyd <lloy0076@rebel.net.au>
  Date: Thu, 30 Nov 2000 22:26:04 +1030

Re: mbs M/bs xyz/s

G'day David,

David Lloyd <lloy0076@rebel.net.au> wrote:
> 
> Can someone tell me what these damned appelations mean?

Sure, or you could visit www.whatis.com - it's much quicker ;]

> mb/s
> mB/S
> (are they the same thing)
> kb/s
> bps
> baud

Baud was the prevalent measure for data transmission speed until
replaced by a more accurate term, bits per second (bits per second).
One baud is one electronic state change per second.

Since a single state change can involve more than a single bit of
data, the bps unit of measurement has replaced it as a better
expression of data transmission speed.

The measure was named after a French engineer, Jean-Maurice-Emile
Baudot.

Baud was first used to measure the speed of telegraph transmissions. 
 
In data communications, bits per second (abbreviated bps) is a
common measure of data speed for computer modem and transmission
carriers. As the term implies, the speed in bps is equal to the
number of bits transmitted or received each second. The duration
d of a data bit, in seconds, is inversely proportional to the
digital transmission speed s in bps:

               d = 1/s

Larger units are sometimes used to denote high data speeds. One
kilobit per second (abbreviated Kbps in the U.S.; kbps elsewhere)
is equal to 1,000 bps. One megabit per second (Mbps) is equal to
1,000,000 bps or 1,000 kbps.

Computer modems for twisted pair telephone lines usually operate
at speeds between 14.4 and 57.6 kbps. The most common speeds are
28.8 and 33.6 kbps. So-called "cable modems," designed for use with
TV cable networks, can operate at more than 100 kbps. Fiberoptic
modems are the fastest of all; they can send and receive data at
many Mbps.

The bandwidth of a signal depends on the speed in bps. With some
exceptions, the higher the bps number, the greater is the nominal
signal bandwidth. (Speed and bandwidth are, however, not the same
thing.) Bandwidth is measured in standard frequency units of kHz
or MHz.

Data speed is sometimes specified in terms of baud, which is a
measure of the number of times a digital signal changes state in
one second. Baud, sometimes called the "baud rate," is almost always
a lower figure than bps for a given digital signal. The terms are
often used interchangeably, even though they do not refer to the
same thing. If you hear that a computer modem can function at
"33,600 baud" or "33.6 kilobaud," you can be reasonably sure that
the term is being misused, and the figures actually indicate bps.
 
> wotever...

All the above was quote directly from www.whatis.com after typing
one keyword search - all credits and attributions go to them.

> I'm totally cofused (again)....

don't fret, there's always tomorrow ;]

Cheers

Leigh
-- 
| "By the time they had diminished | Leigh Hart, hart@dotat.com |
|  from 50 to 8, the other dwarves | CCNA: http://www.cisco.com |
|  began to suspect 'Hungry' ..."  | PO Box 3057 Newton SA 5074 |
|   -- Gary Larson, "The Far Side" | http://www.dotat.com/hart/ |

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