I have an ASUS P5B-VM motherboard for my newish home theatre system. It has an onboard header for S/PDIF output, but no connector. The header has three pins: +5, GND, and S/PDIF-OUT.
ASUS makes a separate accessory back panel connector board for use with this, but I don't have one of those (yet).
Here's a
photograph of it (attached, blurry) from the ASUS estore site. In this, one can see that the S/PDIF output (top right) is merely an RCA jack connecting *almost* directly to the feed from the motherboard.
But before it gets to the jack, it passes through a capacitor, and then a voltage divider (two resistors in series between the the S/PDIF-OUT signal and GND, with the RCA jack tapping from the middle point between the two resistors.
My questions are: what values should I use for the capactor and the resistors, in making my own connector board? Let's assume the motherboard S/PDIF-OUT signal uses TTL logic levels (I can verify this.. just haven't done it yet).
???