|The digital output does not produce a voltage. It is an open collector output, which is effectively a digital switch. Under normal conditions the switch is open and the digital output is floating. When the alarm triggers the switch closes and the digital output goes to near ground. This functionality allows the camera to complete an external circuit when an alarm triggers, for example to turn on a light or some other device. The current and voltage limits for the digital outputs as well as schematics can be found in the back of the camera manual.
FLIR Systems Technical Support