Analogue vs digital interconnects

[Nadfan]

What are the major differences between an analogue interconnect and a digital interconnect? I have VDH The Name Analogue connected between AVR and CD p and Pudney digital connected between AVR and DVD p. Can both be used for similar signal transport or what are the significances? Is one for cd p and the other only for dvd p, or am I just being stupid again? Please shed some light here. 

 

[Shonver]

 

[Norval]

 

[alphabet]

 

[DevillEars]