[VF-102 series] Why the monitor displays nothing or DVR records nothing after the analog camera, VF-102-KIT and cables are well connected?

1.Check the corresponding devices:
　- The analog camera should connect to the VF-102-T – the video
　　transmitter.
　- The monitor / DVR should connect to the VF-102-R - the video receiver.
　　Reversed the connected devices, they’re unable to establish connect.

2.Check the link status LED
　- Check the cable connections of coaxial and fiber patch cord, and make
　　sure both VIDEO and LINK LED are lit.
　- The optical interface of the VF-1020KIT are single mode, single fiber
　　bi-direction transceivers with FC type connector, make sure the fiber
　　patch cord applies to 9/125um single mode.