Null-Modem serial-to-USB cable

[Nicholas Bodley]

On Thu, 03 Apr 2008 20:25:20 -0400, Tom Metro <blu at vl.com> wrote:

>  Here's an "open source" USB to RS232 adapter:
>  http://www.embedded-projects.net/index.php?page_id=165

> I don't know if it has a working DTR line, but it ought to have adequate  
> documentation of the hardware to permit answering that question, and a  
> support community.

I took a look at the schematic ("Schaltplan" in German, I conclude) for  
the higher-numbered version, and it doesn't seem to have more than serial  
data input and output. However, PD6 and PD7 on the embedded µP seem not to  
be assigned, and any good hacker should be able to adapt the board to make  
DTR wiggle. (I can't figure out for sure whether SV2 is the RS-232  
connector, but nothing else seems to be.)

The organization seems to encourage writing of more driver firmware; they  
might reply about adding a DTR output. (If you're careful of static and  
such, you might well use PD6 or PD7 directly connected to whatever you  
wanted DTR to wiggle.)

One US company that is (imho) inspiring, heavily "into" embedded  
microprocessors and some related hardware is Sparkfun:
<http://www.sparkfun.com/commerce/categories.php>
They are an extremely capable, alert, and well-informed bunch who seem to  
keep up with the field really well.

Good luck!

-- 
Nicholas Bodley
Waltham, Mass.

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