Campbell Scientific CC5MPX and CC5MPXWD Digital Network Cameras - Manual (Page 80)

Section 8. Internal Jumpers
8-2
8.2 External Trigger Pull-Up/Pull-Down Jumper
The jumper location for the External Trigger Pull-up/Pull-down location is
shown in FIGURE 8-1. When the jumper is located on the right two pins of
the header (factory default position), there is a 100 kohm pull-down resistor
connected from the External Trigger line to ground. When the jumper is
placed on the left two pins of the header, there is a 47 kohm pull-up resistor
connected from the External Trigger line to 3.3 Volts.
The pull-up resistor would be useful for having contact closures or open
collector output signals trigger the camera. In the case of a contact closure, the
jumper would be moved to the pull-up position and then one end of the contact
would connect to the External Trigger signal and the other end of the contact
would connect to ground. A schematic representation is shown in FIGURE
8-2.
FIGURE 8-2. Schematic Showing External Contact Device