PolySync requires the mount point (commonly an absolute path) to the USB sensor or hardware device stored within the PolySync SDF. For Linux based systems USB devices enumerate within the /dev/ directory. Note that there can be a large number of other devices in this directory. With 1+ USB devices it is best to use discovery applications for identifying the mount point of each device.
The simplest method of determining the directory path of a mounted USB camera is to use the linux application v4lt.
$ sudo apt-get install v4lt-util $ v4l2-ctl --list-devices
UVC Camera (046d:0821) (usb-0000:00:14.0-2):
Integrated Camera (usb-0000:00:14.0-8):
If you're unable to connect to a USB device, ensure that you have permissions to access the devices enumerated in the /dev/ directory:
$ sudo adduser [username-goes-here] dialout