Intel GA-8I915MK-GV Advanced 6 Channel Analog Audio Output Mode (using Audio Combo Kit,Optional Device):

GA-8I915MK-GV Motherboard - 70 -
English
STEP 1:
Secure the metal bracket of the"Surround Kit" to the
chassis back panel with a screw.
Advanced 6 Channel Analog Audio Output Mode (using Audio Combo Kit,Optional Device):
(Audio Combo Kit provides SPDIF output port : optical & coaxis and SURROUND-KIT : Rear R/L &
CEN /Subwoofer)
SURROUND-KIT access analog output to rear
channels and Center/Subwoofer channels. It is the
best solution if you need 6 channel output, Line In
and MIC at the same time. "SURROUND-KIT" is
included in the GIGABYTE unique "Audio Combo
Kit" as picture.
STEP 2:
Connect the "SURROUND-KIT" cable to the SUR_CEN connector on the M/B.