I don't know how you initialize your cameras in code, but if you use the camera name ("cam0", "cam1" etc.) you can find the names of the cameras that are connected to the rio through the rio webdashboard thing (open a silverlight-capable browser to "roborio-TEAM-frc.local" as per
https://wpilib.screenstepslive.com/s...o-webdashboard )
I haven't tested what port each name corresponds to, so I can't help you there. On our team we just cycle throught our cameras until we find the one we want.
Also of note: you can connect to more than two cameras by using a usb hub.