What are these holes on my dedicated sound card for?

inv

Honorable
Feb 14, 2014
17
0
10,520
I've a Xonar DX,

P_500.jpg
,

on its specifications page it says it's

"Analog Output
4 x 3.5 mm jack (1/8") (Front out/Side out/Center-Subwoofer out/Rear out)
Analog Input
1 x 3.5 mm jack (1/8") (Line-in/ Mic-in combo)
Digital
1 x S/PDIF out (1 x Optical (Toslink)/(combo with analog in))
1 x Front-Panel Header
1 x Aux in (4-pin header)",

does any1 know what are the 3 bottom connections,

"Digital
1 x S/PDIF out (1 x Optical (Toslink)")
"1 x Front-Panel Header
1 x Aux in (4-pin header)"

are for?