Transmission time (number of packets times bus period: see “How can I work out the packet size for a wanted frame rate?”)
• Time it takes for the capturing process to wake up after for example blocking on waiting for a frame to be captured The first five delays can be known from the camera’s user’s manual or by measurement or by calculation. The last delay (6) is harder to pin down although you could get an idea by collecting statistics of its average and maximum. First check if your camera’s external trigger input is compatible with the signal levels from your computer’s serial port. It very likely is (most are opto-isolated) but you would want to minimize any risk to the camera. Connect the serial port data-terminal-ready (DTR) line (pin 4 on D-sub-9 connector, pin 20 on DB-25 connector) and the signal ground line (pin 5 on D-sub-9, pin 7 on DB-25) to your camera’s external trigger input.
