[E3-hacking] About connecting to the serial on the E3

[Sean Furey]

On Thu, Apr 04, 2019 at 12:18:56PM +0200, David Given wrote:
> Provided the E3 and the USB device ran off isolated supplies, you might be
> able to get away with connecting the 5V (or whatever) on the USB adapter to
> the GND on the jack. That would cause the logic levels to be interpreted
> inverted.

I'd have thought that would make the USB dev see the E3's 0V - 5V as 5V - 10V, and the E3 to see the USB's 0V - 5V as -5V - 0V.  Which doesn't sound like it helps - am I missing something?

Sean