It has something I thought was for headphones, but it's possibly for microphone. There's a symbol which has headphones with an attached microphone - is that just a microphone port? (I've tried googling, but can't find a standardised symbol list.)
I've looked at audio manager and it only has tabs for speakers and microphone. I've tried updating the driver, but windows says I've got the best drivers installed already (Windows 8.1, if that's relevant).
So it looks like it just doesn't allow headphones, but I'm surprised - aren't headphones pretty standard? We use external speakers that plug in through the headphone jack, that we can't use now.