Asus Essence STX II User Manual page 10

Multi-channel expansion board bridge connector: Connect to the multi-channel
expansion board of Essence STX II 7.1 edition or Xonar H6.
4-pin Molex power connector: Connect to the power cable of your power supply
unit.
STX requires a 4-pin Molex connection to power the card.
Front panel audio header: Connect to the chassis-mounted audio module.
10 Chapter 1: Product introduction