Invisible wrote:
> So, you have some equipment for monitoring temparature sensors and 
> logging their readings. And you supply some software that downloads this 
> data and lets you organise and examine it on a desktop PC.
> 
> You also supply your customers with a blob of software which, when 
> installed on a PC, somehow tricks the PC into thinking it has a new 
> serial port. All data sent to this port is *actually* tunnelled to the 
> little black box.
> 
> So, between the little black box at one end, and the custom software 
> driver at the other end, the hardware and software geniunely believe 
> they're still locally connected, yet actually they can be on different 
> continents.
> 
> Is this a valid solution to a design problem? Or is it a cheap hack?
> 
> [Did I mention that the "software" in question appears to be designed to 
> work with Windows 3.0? Does that change the answer?]
> 

If it is an existing system that needs to be made network 'aware' then 
it is a valid solution, but one that should be taken with caution.

Recently I built something that does exactly that.

I have some GPS modules that speak serial.
I built a custom serial/ethernet module.  But this one is smart - it has 
a buffer and built in web page for basic GPS info.
On the computer I run a ethernet/comm port emulator so that programs 
that expect only a comm port can work.
But one better, the serial/ethernet module allows for multiple 
connections - I can get multiple computers and applications pulling the 
same data on comm ports.

IMHO, a serial-ethernet module should be used as a last resort when 
there is no viable alternative.

If it is a mission critical application, then you are just introducing 
more points for failure.  When one of those points die, then it takes 
all that much longer to debug.


This reminds me of what would be put in at the GM-Saturn plant I worked 
in several years ago.  You kludge a bunch of stuff together until it 
works, then repeat and put 50 of them on the plant floor.  Even tho if 
one of them failed it would stop the production line.  I ran into some 
strange setups - parallel to serial to ethernet to serial to com 
port....  and in one case it took 3 days to figure out what piece failed.


Best of luck!

LAter... Tom

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