The trigger input of The Imaging Source USB, FireWire and GigE CCD cameras is opto-coupled. It permits positive trig- ger pulses with any amplitude between 3.3 and 12 V (24 V using a series resistance of 1 kOhm). If you intend to apply higher pulses please make sure that the current lies between the limits of 3 to 12 mA.

The Imaging Source USB, FireWire and GigE CCD cameras offers two different modes of operation:
Free running: The cameras generate a stream of up to 60 images/s depending on their resolution. To considerably redu- ce the amount of data, the frame rate may be reduced to 30, 15, 7.5 or 3.75 images/s. The exposures length can be set in the range of 100 μs to 30 s via software. Please note, however, that the camera's clock generator determines the actual moment of exposure. Thus, it cannot be controlled externally, but measurable using the strobe output. Therefore, this mode of operation is called "free running".
Trigger: The cameras offer a trigger input to determine the moment of exposure. The exposure begins 4.8 μs after the occurrence of a trigger pulse. The length of the exposure in the range of 100 μs to 30 s can be set via software. The dura- tion of the image readout is the reciprocal of the current frame rate. Once the image readout has finished, the camera is able to accept a new trigger pulse at any time.