Asus P6T with Antec ninehundred case, which audio connector?

[cappaj1]

I have an Antec nine hundred case which has two audio ports on the front of it and a wire with both connectors for either AC97 or HD Audio and I'm to use one or the other. My Asus P6T motherboard supports both according to the manual but I'm not sure which one to use. I just want to be able to plug a mic and headphones into the front of the case occasionally.

Suggestions?

 

[PCTC2]

I believe the default is HD Audio, so just use the HD front panel connector.