I don't know that much about the digital speaker since I never have one yet. All I wonder is if digital and analog signal are really different when they all are from computers which use digital signal as a base. If it's really output as digital, then the digital speaker must have DAC too. Does that sound weird? and why should we have to have a sound card anyway--just to have a digital connector?
That's what I have to figure out next. Surely, I will get one of those soon.
However, what I want to say today is I had a chance to fix one of my friends' computer; he had Sony VAIO with SoundMax AC'97 onboard. There are 3 common connectors--line in, speaker, and mic in. Moreover there is one SPDIF as well. The strange thing is he had plugged the RCA coax + converter to stereo plug to line in connector. He claimed that it worked randomly. I really had no idea how it works; I thought it might be the same as my creative audigy ZS which one connector can handle both digital and analog output. By the way, I have no luck to make it work. All I can find is plain drivers which allow sound card to work properly--there is no option to tweak only a bit. At that time, I'm almost pretty sure of that's his mistake. But I don't know really because I never have this experience. All a guide book, whatever documents from sony.com don't help.
After having no hope to tweak those connector to work digitally, I asked him that he had to have a new cable. Fortunately, he gathered all stuffs from his cabinet and found old computers. What I found is Creative SoundBlaster Audigy 2. Yes! it has S/PDIF output as well and that port is not optical but electrical which is working very well for his cable. :-D Ultimately I can solve his problem then.
Only the question left in my mind: if it's an electrical connector which needs electrons to carry the signal--is it digital really? or it's analog signal with digital encoded inside. If so, it should consider as digital or just analog as same as telephone signal?
Oh I don't believe that I'm an electrical engineer :'( because I think everything is analog by the way :-P Digital is just for any calculations or processes in circuits. Whenever signal-to-noise ratio does matter, thus digital is all the way. (analog is just what we don't realize it's underneath in every single steps)
just to keep it for the archive, so I don’t have to google much :-P I don’t know this is worse than googling when I want. Let’s try =) http://pinouts.ru/connector/ The common thing we should know:-