One USB-6008 to trigger another?

[DAC-novice]

I'm trying to use the digital out from a USB-6008 connected to one laptop, to trigger 2 relay boards and another USB-6008, which is connected to a diffferent laptop. Can all 4 of these items share a common ground? Any other suggestions on how to use the trigger output from one DAC system to provide a trigger signal to the other?

[Tom__Sedlack]

The grounds probably could be connected together but that tends to introduce ground-loops and other undesireable behaviour. I would suggest using an opto-isolator to connect the various systems.  Laptop 1 drives the LED.  The transistor side would trigger the relays and other laptop.  You may need to have multiple opto-couplers depending on how the system is layed out.