KT&C KPC-HDX210M - Manual (Page 13)

6. INSTALLATION
5. Please insert the connection plug from the auto iris lens cable into the auto
lens connector, which is located on the side of the camera.
13
C-mount lens : 10mm or less
CS-mount lens : 5mm or less
*NOTE
When using a CS-Mount Lens, you can attach it directly to camera.
If using a C-Mount Lens, you must attach the ring spacer provided,
otherwise if will crack the image sensor.