I have been asking the same question to no avail I was able to find this per Samsung Tech Support
Here is Samsungs Wiring diagram
1. Nothing (12V)
2. Nothing (GND)
3. Gray (GND (AUDIO))
4. Red (12V)
5. Black (GND)
6. White (N.C)
7. Green (CVBS-)
8. Yellow (CVBS+)
This should help you hook up a BNC adapter to Samsung Cameras.