Axis 2120 User Manual page 58

Appendix C - The Unit Connectors AXIS 2120 User's Manual
58
Digital Input
Used for connecting external alarm devices and triggering images for specific alarm-based events,
the digital input is typically connected to a motion detector (or any other external security device)
for taking images on each occasion that the detector is activated.
Digital Output
The supported transistor output can drive a maximum load of 24V DC at 100mA directly, and by
connecting additional relay circuitry, can drive even heavier loads.From the Administration Tools
you use ON/OFF buttons in the Layout settings to drive the output high or low.