Part Number: ADP7055 Description: Balun - BNC Female to RJ45 75 OHM for Video Category: Cables Video Adapters Baluns Price: $74.44

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Baluns allow you to run a video coax type signal through twisted pair wire. Two would actually be needed to make a connection, one at each end of the twisted pair wire.
Please note: These won't work with CATV signals or to carry CH3 or CH4 from a modulator, composite video has a much lower bandwidth and can be carried through these but the carrier frequencies of CATV or modulated video are too high.