Eric Smith wrote: >Thomas Brandon writes: >> I read a FAQ on digital audio that stated that AES/BEU and SPDIF were not >> convertable. Yet, the only differences I could see where: >> 1) Voltage levels >> SPDIF is much lower voltage level (very easily wrong). > >Somewhat. I've seen people wire them together with no problem. But it >would be nearly trivial to interface them if they don't work directly. I've wired AES/EBU to spdif directly, and it has worked for me with short cables, so I would agree that electrically that you can fudge it, but I wouln't sell a product based on those assumptions (although I suspect it has been done)... >> 2) Protocol >> The framing is different. One uses one more bit for it's protocol (not a >> data bit). > >The framing is the same. The interpretation of the C (channel status) bit >can be either "consumer" or "professional", depending on one of the C bits. >The IEC 958 spec defines both. Some devices don't pay any attention to the >C bit anyhow. In my (limited) experience, the only problem with having the >wrong C format is that a consumer DAT recorder with SCMS will assume that the >digital input is copy-protected. As far as product labeling goes at least, AES/EBU dosn't necessarily mean "professional" subcode and vice versa. I have used semi-pro gear that uses rca connectors for professional AES/EBU code, and vice versa (especially older gear - Sony DTS10(?) comes to mind). You can buy little boxes to remove SCMS from a digital stream, nothing you couldn't do with a 56k DSP, I'm not sure about bit-banging it with a PIC though! The pros talk about "Clock Jitter" - it seems that the digital signal is often unbuffered and that the DAT work clock is synced to the incoming data stream (?) so clocking innacuracies are heard at the output - go figure. Ross.