The Digital Master can connect to digital inputs such as switches, buttons, contact closures, etc AND it can connect to 5v outputs with a low current draw (see Digital Master - Power specifications) such as LEDs, and can turn them on and off digitally. It can also connect to the Isolated Breakout.
We recommend you watch the Using Digital Inputs and Using Digital Outputs tutorials.
To connect anything to a Digital Master, you will need:
To connect a Digital Input, screw the stripped wires into breakout in the configuration below. The pairs must always go into adjacent terminals. It does not matter which way around the wire go as switches do not have polarity (unless there is a diode in the circuit forcing a direction).
Connect an ethernet cable to the breakout and then into a port on the Digital Master. Once connected, you can now patch this channel to a digital input channel in COGS.
To connect a Digital Output is the same as a digital input, except the polarity of the cables must go in the order - , + from the left of your RJ45 breakout (as shown above).