[En-Nut-Discussion] Problems with serial port

[scostas]

Hi all!

What voltage levels uses shows the Ethernut 3 serial port?

I ask this because I have a misterious failure with it. I have an
EZIO-100 LCD display, which works with a standard RS-232 port. I connect
the LCD to a Ethernut 2 and it works fine. I connect it to my PC and
works fine. I connect my Ethernut 3 to my PC and it sends the bytes fine
(and the PC receives them fine), but I connect the LCD to the Ethernut 3
and it doesn't work.

The LCD uses a curious method to adapt the RS-232 levels to TTL levels:
it sends the signal through a resistor directly to one E/S port of its
PIC microcontroller, and uses the internal diodes (which gives
protection in case of overvoltages) to cut it to the right levels. Can
this circuit make it fail?

Thanks.