Use this cable to send a PWM pulse to the Survey3 and Survey2 cameras to perform various functions. See the diagram below for the HDMI pins that are connected and the required PWM pulse to send depending on the function you want to perform.
For both Survey3 and Survey2, to trigger the shutter (take a photo) send the camera a 2000us pulse. Use the 1000us as a neutral, do not do anything level.
For Survey3 cameras, you can also send the camera a 1500us pulse width to have the camera enter USB Media Transfer mode. If the camera is connected to a computer using the USB/POWER/FPV port, when in transfer mode the camera's SD memory card will then become mounted to the computer and you can access it just like the SD card was plugged into the memory card reader on your computer. This is very useful if using a companion computer such as on a drone, in that you can then extract the images from the camera and onto the computer's memory. Then you can do anything you want, such as process the photos or store them onto an external memory stick or SSD to easily take the photos off your drone.