I’m a big proponent of DIY PC building and I tend to describe it as “relatively straightforward.” For the most part, everything just plugs in where it should. But there is one aspect of putting together a new computer that even I don’t enjoy: the front panel I/O connectors.

The front panel is a bizarre array of USB headers, audio connectors, and push-button pins that are so fiddly and complicated, and often the cables only seem to just reach the motherboard spots where they need to go, so plugging them in can be a challenge. Plus, the connectors you need to plug in can vary depending on your PC case.

Unlike RAM and graphics cards, front panel I/O connections aren’t so straightforward. Here’s a quick breakdown of the different I/O connectors you’re likely to see and what they all mean.

The most important connector you need to plug in correctly is the power switch. This is the one that connects the physical power button on your PC to the motherboard and allows it to tell your system to start. Without it, you can’t physically boot your PC (unless you’re willing to short the connectors, but that’s outside the scope of this article).

Jon Martindale / Foundry

The power switch is usually a small black plastic header, with two female ports for the motherboard’s pins to slot into. It’s often accompanied by other front I/O connectors that may be clumped together, since they all plug into the same area on your motherboard.