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Technical Information on Digital Interfaces
Edgar Bueltemeyer
In the email digest Sam Glass wondered if anyone had been able to get any hardware information from Terratec regarding their implementation of the coaxial digital in / out. For example, signal voltage levels, and in particular the voltage range.

"I was just reading about the AES3 specifications: the frame structure is the same but the voltage levels, (3-7v pk-pk), may be different. A company in America make cables to connect between the 7 pin connector on the bottom of my Sony DAT and the coax in & out. There's an active version which does all the signal level translation, and a passive that leaves the levels alone and apparently works with most equipment..."

Reason enough for Edgar Bueltemeyer to elaborate on this topic. Reason enough for us to preserve his contribution for others who might need this information.
The overview
  • S/PDIF:
    Sony / Phillips or IEC598 digital Interface
    Peak-Voltage: 0.5 V
    Impedance: 75 Ohms
  • AES/EBU:
    professional Version of digital Interface used on Studio DATīs etc.
    Peak Voltage: 5V
    Impedance: 110 Ohms
  • The interface on SONY portable DATīs:
    TCD7 and TCD8: The signal FORMAT coming out is actually S/PDIF, but the voltage differs. Itīs 5 V.
    This signal is electrically seen TTL.
  • TCD100:
    The same except the voltage. Because the TCD100 uses just 2 batterys the voltage is 3V.
    This signal is electrically seen low voltage TTL.

The choices

  1. Buy the optical cable
  2. Buy the active coaxial cable

    These are as far as I know for the TCD7/8 (at least the ones I have found in the net)
  3. The passive coaxial cable
  4. Look for some TTL to Optical or Coax converter circuits in the internet and build them yourself (actually much cheaper).
  5. What I did: Look for the DAT-page of Heiko Purnhage: http://www.fet.uni-hannover.de/purnhage/dat/dat.html

Build yourself a connector for the 7 pin-plug and connect the signal-pins to the coaxial input of the EWS. I used small pins of PCB-connectors which are available very cheap at the local electronic store. Then some shielded cable , and 2 cinch plugs. All I can say is. that this worked for me (TCD100 - EWS). I donīt know if the EWS survives 5V (TCD7 and 8). Could someone try it out? ;-)

PS: Please donīt blame me if you burn your DAT-Deck, Terratec Soundcard, Computer, Your house, your car or anything after trying out my solution. If anything like this happens or the whole universe is snoozed into the nose of a giant dog (like in Hitchhikers Guide to the Galaxy).
IT IS NOT MY FAULT!
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testtube
toppage

Đ 1998-1999, Computer ConText, Amsterdam, The Netherlands.

Latest update on page: 19-09-99
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