The UCC transmitter has a filter circuit for signal overlaps with video downstream, and modulating input control signals such as UART, Pelco with 145kHz or 840kHz to access the remote camera for PTZ control, menu control and firmware downloading.
PoC(Power over Coax) is a technique to supply power, downstream video and upstream UCC in a overlapped form over a coax cable. Also, it has not only electrical circuit protection but also filter circuits to avoid signal crosstalk with video signals.