Nexus One's 3.5mm headphone jack accepts standard 3.5mm plug?

As you know, the Nexus One comes with a **4**-segment 3.5mm headphone jack, whereas the standard 3.5mm plug has 3 segments. I visually compared a standard 3-segment 3.5mm plug with the **4**-segment 3.5mm plug that comes with the original Nexus One headset and they seem identical in length. My only concern is that plugging in a standard 3-segment into this **4**-segment jack will damage the Nexus One. Better safe than sorry... so instead of empirically plugging in the standard 3-segment plug in the the N1 just to see whether it causes a fatal short or not, I prefer to ask those who are already knowledgeable with this: Is it **safe** to use a standard 3-segment with the N1 headphone jack?