Here is a prime example of blatant illogical thinking on the part of the media:
http://www.cnn.com/2002/TECH/ptech/03/07/led.sno op ing.reut/index.html
Keep in mind I've done embedded modem code, and my primary technical job at work is to deal with fault situations, including displaying status codes on LEDs so I'm familar witht he technology and its limitations. Here's what's wrong with this article:
1) LED's are very slow devices. That means they can only turn off so many times in a second - on average, 50 times a second. That means *50* baud, which is about 6 characters in a second. There is no technical way that these LEDs can turn on and off fast enough to support even the slowest of modems! It's like driving at 500 MPH and snapping 6 pictures over the course of 50 miles and saying that you can figure out what's in between the pictures. Not technically possible.
2) The author makes the assumption that the blinking lights are actually connected directly to the data stream. This isn't true! One problem we had with our modems initially is we did have the data stream tied to the lights. Once the speed of modems edged up (we're talking 9600bps, here folks, so this was a LONG time ago), the data was toggling so fast that all we could get out of the status LEDs was a dim glow. So we wrote code to keep the status LEDs on for a minimum period of time so they'd actually show up.
3) The author knows nothing about ATMs and their protocols. Even if internal modems built in to ATMs (to which almost all are internal with no indicator lights of any sort), having the data stream, byte by byte will not be a repeatable sequence anyway. There is a trust set up between each ATM and their servers and no two transactions are identical. The stream is encrypted. When was the last time you saw any LEDs on ATMs?
4) The article infers that one can even detect network traffic from the LED. Come on - an LED capable of 50 baud revealing the actual traffic on even something as slow as 10 megabit network?
5) Most of the LEDs that people see on devices don't display any critical information anyway. Power status, fault status, drive activity, etc.. is most of it.
It's asinine things like this that just make me want to scream. They spread fear, uncertainty, and doubt based on factless speculation to promote themselves to groups of people who don't know better.
Don't ever believe anything technical you read in the media. It's almost always wrong.
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Here is a prime example of blatant illogical thinking on the part of the
o op ing.reut/index.html
media:
http://www.cnn.com/2002/TECH/ptech/03/07/led.sn
Keep in mind I've done embedded modem code, and my primary technical job
at work is to deal with fault situations, including displaying status
codes on LEDs so I'm familar witht he technology and its limitations.
Here's what's wrong with this article:
1) LED's are very slow devices. That means they can only turn off so many
times in a second - on average, 50 times a second. That means *50* baud,
which is about 6 characters in a second. There is no technical way that
these LEDs can turn on and off fast enough to support even the slowest of
modems! It's like driving at 500 MPH and snapping 6 pictures over the
course of 50 miles and saying that you can figure out what's in between
the pictures. Not technically possible.
2) The author makes the assumption that the blinking lights are actually
connected directly to the data stream. This isn't true! One problem we had
with our modems initially is we did have the data stream tied to the
lights. Once the speed of modems edged up (we're talking 9600bps, here
folks, so this was a LONG time ago), the data was toggling so fast that
all we could get out of the status LEDs was a dim glow. So we wrote code
to keep the status LEDs on for a minimum period of time so they'd actually
show up.
3) The author knows nothing about ATMs and their protocols. Even if
internal modems built in to ATMs (to which almost all are internal with no
indicator lights of any sort), having the data stream, byte by byte will
not be a repeatable sequence anyway. There is a trust set up between each
ATM and their servers and no two transactions are identical. The stream is
encrypted. When was the last time you saw any LEDs on ATMs?
4) The article infers that one can even detect network traffic from the
LED. Come on - an LED capable of 50 baud revealing the actual traffic on
even something as slow as 10 megabit network?
5) Most of the LEDs that people see on devices don't display any critical
information anyway. Power status, fault status, drive activity, etc.. is
most of it.
It's asinine things like this that just make me want to scream. They
spread fear, uncertainty, and doubt based on factless speculation to
promote themselves to groups of people who don't know better.
Don't ever believe anything technical you read in the media. It's almost always wrong.