The serial port being used here was initially just a couple pins on the=20
PCB that I was using with a serial LCD for diagnosis.  When the board=20
was enclosed & mounted to the truck (for on-road testing), I routed=20
those wires to two spare pins so the LCD could be outside the enclosure=20
when I needed to test.  Later the customer wanted to change some=20
parameters (in EEPROM) so that port became the interface to the laptop. =20
Hence the external RS232-to-TTL converter.  The next revision of this=20
PCB will have a second MAX232 on board for this purpose.

Cheers,
-Neil.


On 11/13/2014 11:46 AM, alan.b.pearce@stfc.ac.uk wrote:
> And also begs the question, why isn't the RS232 conversion permanently in=
 the box?
>
>

--=20
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