How many doors can one Nold device control?

Every device has two separate outputs called OUT1 and OUT2. You can setup these outputs as individual devices/keys in the app, so you can control them one by one and share access to them separately. 

This is useful if you have a twin garage for example, since you can use a single Nold Open device to control both doors. For entry gate, you can use one of the outputs to control the pedestrian function of your gate for example. You can also change the operation modes for one of the outputs, so you can control your LED lights with the second output, while the first is connected to your garage door for example. (Learn more about the operation modes here)

You can also connect more than one thing to a single output, but this means that your doors will open at the same time.