A critical technological development in high-definition video was the development of cords that can transmit enough information to connect a high-definition video player to a high-definition screen. The cable that was developed is the high-definition HDMI cable. Many older video playback devices, however, still exclusively have output jacks for the older technology, RCA cables. This can present a problem if you have a newer video display with only an HDMI input. Fortunately, simple hardware converters allow an RCA cable end to be connected to an HDMI cable end.
RCA cables have been in common usage for sending video signals since the 1970s. They come in a variety of shapes and colors, with the most common configuration being a single transmission cable with three color-coded plugs on the end. Although RCA cables are fairly universal and can be used on most TVs and projectors, RCA technology is limited in how much data can be transmitted. For this reason, RCA cables cannot transmit a high-definition signal. As high-definition televisions become more common, RCA cables are being replaced with new, high-definition cables.
HDMI cables were developed to facilitate sending a high-definition signal from a video playback device to a high-definition screen. These cables can support a much stronger signal, transmitting up to 1080 pixels at 60 frames/second. This is the highest available resolution for digital video at this writing and cannot be transmitted over RCA cables. Due to the superior transmission capabilities of this technology, HDMI connectors are becoming more common in contemporary TVs and projectors. It is likely that HDMI cables will soon be considered the standard cable for transmitting audio and video in home audio-visual devices.
Converting RCA to HDMI
If you are connecting a video player to a screen in which one of the devices only has RCA jacks and the other device only has HDMI jacks, it is necessary to use a converter to transmit the video and audio signals. This can be accomplished either through a converter cable or a converter box. In both cases, the converter have a female RCA input and a female HDMI output. From your standpoint as a user, it is a simple conversion process. Simply plug the RCA cable into the converter's RCA input and the HDMI cable into the converter's HDMI output.
In certain video device configurations, it is possible to have a high-definition video player and high-definition screen, but still have RCA cables involved. This only occurs if an extra device is in the system, such as a signal splitter or game system, or if you simply do not have an HDMI cable. If RCA cables are used at any point when transmitting a high-definition video, the result is a downgraded signal. Since the RCA cable cannot transmit enough data for a high-definition signal, it functions as a kind of choke point, preventing the ultimate signal from being high definition.