CCTV Articles

BNC to RCA Adapters

There are many different types of connectors used in digital video security and surveillance systems such as the BNC to RCA adapter for example.  In this article we’ll try to cover BNC and RCA connectors and adapters.

BNC Connector

BNC is an acronym for Bayonet Neill-Councelman.  Paul Neill and Carl Councelman.  Neill worked for Bell Labs and invented something called the “N” connector.  Carl Concelman worked at Amphenol and invented something called the “C” connector.  Octavio Salati, a graduate of the Moore School of Electrical Engineering of the University of Pennsylvania filed a patent for a connector for coaxial cables that would solidly hold the cable but would minimize wave reflection or loss.  The patent was made official in 1951.

BNC connectors (the ones referenced above in BNC to RCA adapters) are made in either 50 or 70 ohm versions to match the impedance value of the cable that they will be connecting.  There is a male BNC and a separate female BNC connector.  The two fit together with a twist so that the connectors are actually latched together – very similar to the way bayonets latch onto their respective infantry rifles.

There are about three different ways of attaching a BNC connector to corresponding cable (for digital video security systems that cable is usually RG59 coaxial cable).  First, the connector maybe twisted on to the end of a properly stripped RG59 cable.  Second, the connector maybe crimped on to the end of a properly prepared RG59 cable using a special crimping tool made specifically for that purpose, or lastly, it may be compression crimped using a special tool and compression BNC.

Some common uses for a BNC connector besides the digital video security industry include:

  • amateur radio antennas
  • aviation electronics
  • test equipment
  • analog and serial digital interface video signals

RCA Connector

RCA connectors resemble more of a plug shape and are commonly used for connecting DVD players, VCRs, and other audio or video devices.  RCA is an acronym for Radio Corporation of America which created the connector sometime in the 1940’s for the purpose of connecting mono phonograph players to amplifiers.

They may be used for a variety of functions some of which hey were designed for and some that they were not such as:

  • Power connectors
  • Radio Frequency Connectors
  • Loudspeaker cables
  • Digital Cameras and Video Recorders

RCA plugs are often color coded to make them easier to detect. Here’s a list of RCA color coding:

  • Composite video – yellow
  • Right sound – red
  • Center sound – green
  • Left surround sound – blue
  • Right surround sound – gray
  • Left back surround sound – brown
  • Right back surround sound – tan
  • Subwoofer – purple
  • Digital Audio (S/PDIF) – orange
  • Component analog video (YPbPr) – Y – green; Pb – blue; and Pr – red
  • Component analog vide0/VGA (RGB/HV) – B -blue; Horizontal sync/composite sync or H/S – yellow
  • V (vertical sync) – white

BNC to RCA Adapters

As you can see there are several uses for both BNC and RCA connectors.  Also, some of the functions can use either BNC or RCA connectors of there is some overlap in use with each connector.  For example if you were installing your own home digital video security system and you want to use an external monitor or television you may encounter a problem.

BNC connectors were typically used for special functions and often were used instead of RCA plugs because they couldn’t be pulled apart once locked together and you could purchase BNCs to match the impedance of the system.  Also, BNCs were designed to be used by commercial vendors and professional installers more often then the average homeowner as the installer was more apt to have the right compression tools to attach the fittings.

Therefore, monitors designed for use in the digital security video industry almost always have BNC input connections.  However, today’s flat screens TVs have many different input options, including RCA, HDMI, etc., but they seldom include

BNC connectors.

How can this situation be corrected?  By simply using BNC to RCA adaptors.   These adaptors are easy to install and save you the headache of re-wiring, or not being able to use a cert monitor because all it has is RCA plugs.

If you need more information on connectors or BNC to RCA adapters please contact one of our security experts, they’ll be glad to help.



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