Asus Xonar DS,DX or DG

Hello
its my first discussion about sound card i have logitech z906 and i want a normal sound card that support digital connection that my z906 can handle my choices are

Asus Xonar DS,DX And DG

http://in.asus.com/Multimedia/Audio_Cards/Xonar_DS/
http://in.asus.com/Multimedia/Audio_Cards/Xonar_DX/
http://in.asus.com/Multimedia/Audio_Cards/Xonar_DG/

where i am confused is in Xonar DS in specification its written in specification That
😀igital
1 x S/PDIF out (1 x Optical (Toslink)/(combo with rear out))
what does that Toslink/combo with rear out means ??
do i have to spend addidional money to buy a digital panel
same as in DX

only in DG i can see that there is one extra port port header at back i dont know for what it is
is it for S/PDIF but mine speaker has some circle type S/PDIF

Can anyone guide me
 
I have used both the DX and DG. Both are better than onboard audio, but I prefer the DX which is quite a bit more expensive. I suggest running digital optical or coaxial from your motherboard to ports 3,4 or 5 on your amplifier and skipping the soundcard altogether to start. If you don't like the sound, get a sound card and use the analog outputs to connect to your speakers amplifier (green, orange and black ports). I recommend the DX as its still reasonable as far as price goes and sounds great if you decide to splurge on a sound card.
 

I dont have digital connection in my board and i already have sound card "creative x-fi xtreme audio
http://us.store.creative.com/Creative-Sound-Blaster-XFi-Xtreme-Audio/M/B000IZC0GO.htm

its old and dont have digital connection
what i want is good audio quality with digital connection
 

ok so S/PDIF optical out cable comes with DG
which cable i needed so that it connects to my speakers