This cable plugs into the X-Box AV port. It includes a video amplifier which boosts the X-Box video signal to the level required by arcade monitors. It also includes a sync separator chip (inside the D-Plug housing). You can also plug in a pair of amplified speakers for sound. The picture shows all connections required for an X-Box to arcade monitor, speakers and controls.
IMPORTANT! This cable only works with 15Khz arcade monitors. It will NOT work with PC monitors. If your arcade monitor is a multi-frequency model (eg W-G D9500) and has a VGA connector then the J-PAC adaptor (below) is the best choice.