Re: Electronics question

[Kevin Hawkins <yahoogroupskh@xxxxxxxxxxxxxx>]

Could it be anything as simple as some configuration parameters for
the
specific Avocent port in use that causes the port to assert DTR ?  3.5V
is not a large enough voltage here to work with most RS232 equipment
-and obviously isn't enough to power a 5V regulator.  The port was
'open' when you made this measurement I assume.

Ant's suggestions is neat way around this - albeit requiring a secondary
PSU.

K

ant wrote:
> Hi Paul,
>
> Yeah you're pretty much there:
>
> 1) disconnect the DTR line from your circuit (belt and braces)
> 2) connect the +ve wire from a 9v DC PSU to pin 1 of the 78L05
> 3) connect the ground wire from the 9v DC PSU to one of the
> regulator's ground pins (I can't read the schematic, there might only
> be one ground pin, depends on the package)
> 4) leave the RXD and GROUND connections to the serial port
>
> cheers
>
> ant
>
>
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