Audio help needed

I just got a couple year old Sony SACD/DVD changer from a friend that never even opened it, I plan on using it as a component in my home theater system primarily as a CD changer since I went with a higher end audio system and not a home theater in a box unit with a changer included.  I'm still kind of learning about all this stuff though, and I noticed the changer has a 6 cable 5.1 audio connection system, it also has a digital optical toslink connection.  \\

 Which one is better quality?   My home theater is a 7.1 surround system, and I know 6.1 and 7.1 have become more prevelant since this model changer was released, but does Toslink support 6.1 and 7.1 surround? I'm using HDMI with my newer equipment, and I kind of missed the couple years where 5.1, 6.1 and 7.1 started coming into dominance.  I just want to optimise this older component for what I can, so any help would be appreciated.  Thanks.

Also, does that thing have digital coaxial? Choose that over Toslink(digital optical). Better bass response

Also, does that thing have digital coaxial? Choose that over Toslink(digital optical). Better bass responseKodai_kun

Toslink and digital coax are identical in every way once the data gets to the reciever. Neither one willl result in a better or worse signal. It's just a digital bitstream

Toslink goes through an extra conversion though.  It has to go from bit stream to a light pulse, then back to bit stream.  The advantage to it is that it is not susceptible to interference, while digital coax is.  But coax is a direct link without the the extra conversion.  So I always say that if your connection requires 2 meters or less use coax, but if you need more than 2 meters use toslink.

But for the guy's SACD player you have to use the 6 channel analog.

Toslink goes through an extra conversion though. It has to go from bit stream to a light pulse, then back to bit stream. The advantage to it is that it is not susceptible to interference, while digital coax is. But coax is a direct link without the the extra conversion. So I always say that if your connection requires 2 meters or less use coax, but if you need more than 2 meters use toslink.