For being late you have a very sound mind with a very good idea.

As you say only use 1 wire for negative is poor design.
This wire will be the limiting factor.
It's like trying to get 2 pipes of water through a single pipe of
water of same size as each individual pipe of water before..
You will not be able to push through more water then what the last
pipe can handle (in this case the single wire).

Better to use a solution that will reset the unit when the wire is in
open state for more then X time period that way when you press the
button it will run the system on 1 wire only (might cause the radio to
shut down or perform poorly if it is like many other systems I seen).


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 Eje Gustafsson                       mailto:[EMAIL PROTECTED]
The Family Entertainment Network      http://www.fament.com
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BF> I have to ask this as I wonder if it might be contributing to some of the 
BF> stability problems.  The powershot uses pins 7 & 8 for positive and pin 5 
BF> for negative.  Pin 4 is used for the device reset button.  PoE typically 
BF> uses two wires for each lead so that the voltage and current drop is 
BF> minimal.  By only using one wire for the negative lead the voltage and 
BF> current drop significantly.  In lab conditions, this won't make a huge 
BF> difference.  However, once temperature is factored in the possible drop on 
BF> 100 Feet of cable and a 12 volt supply is likely to be below minimal 
BF> operational limits.  Has all this been considered in the design?

BF> I think that changing the reset button from a normally open type to a 
BF> normally closed type and then adding a transistor and probably a diode to 
BF> the radio would be more effective.  This way the reset wire is always 
BF> acting as a negative lead except when performing a reset.  The additional 
BF> transistor would invert the state of the reset button and provide the 
BF> circuit a connection to the additional negative lead.

BF> It's late at night but I think my thoughts are clear.  Any ideas, thoughts, 
BF> comments?

BF> --Blaine

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