Quick answer: Red is right audio, white or black is left audio, and yellow is composite video. Component video uses green for Y, blue for Pb and red for Pr, so red appears twice in a five-cable bundle. Orange or black often marks digital coaxial audio. Colours are a convention, so verify at both ends.
RCA Cable Color Codes: Red, White, Yellow and Green Explained
The colours on RCA plugs are a convenience, not a law. Red for right and white for left is nearly universal for stereo audio, yellow for composite video is common, and the three-wire component set uses green, blue and red. The trouble starts when two different reds appear in the same bundle: one is right audio and the other is the Pr component channel. Reading the colours correctly, and knowing when to ignore them and trace the cable, prevents a surround system from playing dialogue out of the wrong speaker.
The Stereo Pair and Composite Video
The original three-cable RCA set carries left audio, right audio and composite video. White is left, red is right, yellow is the composite video signal. This set appears on DVD players, older games consoles, set-top boxes and many camcorders. The colours make a three-plug bundle easy to connect in the dark, but they do not indicate signal direction. A cable with two red plugs is usually a stereo pair, not a video channel, so read the moulded labels as well as the colour.
White, Red and Yellow
White carries the left channel, red the right, yellow the composite video. If the left and right are swapped, the stereo image inverts and centre dialogue moves off screen. If video is plugged into an audio input, the result is usually a hum or a blank screen, not damage.
Black Instead of White
Some manufacturers use black for left audio and red for right, particularly on pro audio and older European equipment. The convention is the same, the colour is different. Always check the label or the manual before assuming black is ground.
Component Video and the Second Red
Component video splits the picture into three signals: luminance and sync on Y, blue difference on Pb, and red difference on Pr. The connectors are green, blue and red. The red used for Pr is the same colour as right audio, which is the source of most wiring mistakes in a five-cable bundle. A component set is not interchangeable with a composite set: the signals are different, and swapping them produces a green or magenta picture rather than a clean image.
Green, Blue and Red
Green is Y, which carries brightness and sync. Blue is Pb, and red is Pr. The three signals reconstruct the colour image in the display. Component video supports higher resolution than composite, up to 1080i on most consumer equipment.
Five-Cable Bundles
A five-cable bundle carries component video plus stereo audio: green, blue, red for video and white, red for audio. Two reds are present. Label both ends before pulling the bundle through a cabinet, because colour alone cannot distinguish them.
Digital Audio and Other Colour Uses
Digital coaxial audio often uses an orange RCA plug, and sometimes black. The signal is S/PDIF over 75 ohm coax, and the cable should be a 75 ohm video-grade cable rather than a thin audio lead. Some systems use purple for a subwoofer, green for a trigger, and grey for remote control. These are manufacturer conventions, not a universal code. The only reliable rule is that the colour must match at both ends and the label must match the signal.
Orange and Black for Digital Coax
Orange is the common marker for coaxial digital audio. The cable must be 75 ohm and should not be replaced with a generic stereo lead, because impedance mismatch causes reflections at the bit rate. Keep the run under a few metres for consumer gear.
Subwoofer and Trigger Colours
Purple is often the subwoofer output, and mono subwoofer cables use a single RCA. Trigger and remote jacks may use green or grey and carry low-voltage control, not audio. Connecting a trigger output to an audio input can cause a thump or damage.
Wiring, Testing and Avoiding Mistakes
Before connecting a bundle, label both ends with the device and the channel. Start with the video or the main pair, confirm the picture and the channels, then add the rest. If a channel is missing, swap the cable at the source end first, because that is easier than reaching behind the display. Test continuity with a meter when a cable is suspect, and keep a short known-good lead for fault finding. Colour is a hint; continuity is proof.
A Simple Test Sequence
Connect one source and one display, then test left, right and video one at a time. Use a test tone or a known stereo recording with distinct channels. If the channels are reversed, swap the red and white at one end and label the correction.
When Colours Mislead
Aftermarket cables sometimes use arbitrary colours, and imported equipment may follow a different convention. Trust the moulded label and the manual. A cable with red, white and yellow plugs can still be wired for a different pinout if it was repaired.
RCA colour conventions and signal types
| Colour | Signal | Impedance | Typical device | Notes |
|---|---|---|---|---|
| White or black | Left audio | Low | TV, amplifier | Analogue line level |
| Red | Right audio | Low | TV, amplifier | Also used for Pr |
| Yellow | Composite video | 75 ohm | DVD, console | Standard definition |
| Green | Component Y | 75 ohm | DVD, set-top | Brightness and sync |
| Blue | Component Pb | 75 ohm | DVD, set-top | Colour difference |
| Orange | Digital coax | 75 ohm | AV receiver | S/PDIF audio |
Real-World Application Scenarios
A living room connects a DVD player to a television with a three-plug yellow, white and red lead, and the colours map directly to the panel. A home cinema connects a component source with a five-cable bundle, labels both reds before pulling it through the wall, and avoids swapping right audio with Pr. A hi-fi system uses an orange digital coax lead between a CD transport and a DAC, keeping the cable short and 75 ohm.
Related Guides on This Site
For connector and cable selection, read the RCA connectors guide and the component video with audio reference. Stereo jack wiring is covered in the RCA jack stereo cable guide, and a buying checklist sits in the best RCA cables guide.
Frequently Asked Questions (FAQ)
Q: What do the red, white and yellow RCA cables do?
A: Red is right audio, white is left audio and yellow is composite video. The three form the standard analogue AV lead. If the audio channels are reversed, the stereo image inverts and dialogue moves off centre.
Q: Why are there two red RCA plugs?
A: One red is right audio and the other is the Pr component video channel in a five-cable bundle. They carry different signals. Label both ends before installation so the two reds are not swapped.
Q: Is RCA colour coding a standard?
A: It is a widely followed convention, not a formal standard. Manufacturers may use black for left audio or different colours for control signals. Always confirm with the moulded label or the manual.
Q: Can I use a yellow video cable for digital audio?
A: It will usually work because both are 75 ohm coax, but the cable may not be rated for the digital bit rate. Use an orange or dedicated 75 ohm digital coax cable for S/PDIF, especially over longer runs.
Q: What happens if I plug audio into the video input?
A: Usually no damage, just no picture or a distorted image. Video into an audio input may produce a hum or a buzz. Power down before changing connections to avoid a thump through the speakers.