SERIN2 Receiving Wrong Data

[Ioannis]

that can't be right because

my next guess is that device A is running on 3Volts
this guessing game has got longer legs than i expected

I think it can be right since Serout/Serout2 happens in a async rate. USB is fast but in any case the soft Serial is interrupted randomly.

The logic analyzer catches one instant of this.

Lowering the baud rate helped because of that interrupt thing. Lower baud has more time on every bit and the fast USB gets away.

I have long that I abandoned software serial port use because of such matters.

Ioannis