A: BNC connectors are miniature quick connect/disconnect radio frequency (RF) connectors used for coaxial cable that work with video and ethernet applications.
Q: What does it mean when a connector says it is 50 ohm or 75 ohm?
A: BNC connectors are most commonly made in 50 and 75 ohm versions. Video and DS3 Telco central office applications primarily use 75 ohm connectors, while 50 ohm connectors are used for data.
You can easily tell the difference between the two by looking for the dialectric. The 50 ohm connector features a white dialectric surrounding the center pin, while the 75 ohm BNC connector is surrounded by air (no dialectric).
50 ohm and 75 ohm BNC connectors will mate with each other. At frequencies under 10 MHz the impedance mismatch will not have any affect. If you are above 10 MHz the chances of signal distortion become more significant.
