Digital Output Primer
From Phidgets Support
There are two types of digital outputs:
- Open Collector Digital Outputs, which are solid-state switches that short the output line to ground.
- InterfaceKit Digital Outputs, like the ones on a 1018 or 1019, which output either 5V or 0V depending on what state they're set to.
When in doubt, you can find more information on the User Guide for your specific product.