Hello Thorsten, Thanks for answering. The required trigger time I don't know actually, one thing I know I can trigger it with a +5V trigger signal from my waldorf pulse +, so a simple +5V signal for 1 ms or a little more would probably do the trick, but I'll want to leave options open to make use of the other 6 pins in a later state (probably I'll try to build a couple of modules from Hallucogen's 808 project). Does serial chains mean that it's only possible when you use an DOUT with shift registers in combination with the 128IO application (I see some shiftregister related codelines)? Tijs BTW Big respect to what you've realised with the Midibox project. I never saw such a well-documented midi/audio projects site on the I-net.