Switching S/PDIF

[Martin Czech]

> Y-ellow Y'all.
> 	I'm after some references of S/PDIF electrically speaking. If memory
> serves it's just RS422/425 or something. Not that I know anything about
> that either off hand.
> 
> I find I have several sources and destinations of S/PDIF these days and I
> simply want to be able to switch them around. And I want to do it
> electronically rather than manually with switches. Some switches also
> attenuate the signal as well I've noticed so I'd like to 'receive, switch
> and buffer' the signals. I was thinking of using a cross point switch so I
> need to think about a suitable receiver for the inputs and buffers for the
> output. And hopefully using nothing terribly special and un-obtainable. IE:
> I have some crosspoint switches but nothing special to buffer with. And I
> probably can't obtain the actual parts round here anyway. So if it can be
> done with a bunch of TTL or CMOS it would be good.
> 

Electrical S/PDIF seems to be very simple, just a cmos/ttl buffer and a
75 resistor and a schmitt trigger gate with 75 Ohm parallel on the other side.
I always use (short) audio cable and don't care about impedance.
Longer lines may need the correct 75 Ohm, of course.

So, an electrical S/PDIF crossbar should not be so hard to do.

The optical part is a bit more difficult, because you need these
special opto plugs and sockets with built in led. I found
those hard to get.

Somebody showed me some links about that topic, and I know that
I made some hardcopies, I have them at home. I think these mails should also be
in the archive.

If you can't find anything, I could look it up at home.

m.c.