M-AUDIO CO3 - Manual (Page 5)

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in the "Power" button. The CO3 will always power on with TOSlink Optical
S/PDIF as the source selection, and "Pass-Thru" selected as the SCMS
setting. From the front panel of the CO3, select the input source setting that
matches the format of your input source. Optionally, set the SCMS mode to
its desired setting (more specific information about this is coming later in the
manual).
NOTE: Although it is acceptable to change the various settings of the CO3
while power is turned on, you might hear small bursts of noise while
switching. This is normal as it takes a small amount of time for external
devices to "lock on" to a digital data stream after the switching takes place.
Now, depending on what input you are using, and what the SCMS setting is,
the CO3 will automatically convert the input stream to the output stream(s).
Making sure the volume control on your receiving digital device is set low,
power up the device. It should now lock onto the converted digital stream
from the CO3. Depending on the product, the receiving device may require
some configuration in order to accept data at its digital input port.
Advanced Information
Inside the CO3, there are many different conversions to be made depending
on the front panel settings and the characteristics of the actual incoming
digital data stream. This section describes the various actions taken by the
CO3 in various circumstances. The various CO3 modes are also
summarized in the table at the end of the manual.
SCMS Modes
SCMS or "copy protection" bits are present in S/PDIF data streams (on the
CO3’s RCA and TOSlink connectors) only. The AES/EBU specification does
not define an SCMS capability and therefore the digital streams at the CO3’s
AES/EBU jacks carry no SCMS information. When converting from S/PDIF
to AES/EBU, the SCMS bits must be removed from the digital stream
because there is no place for them in the AES/EBU output stream. When
converting from AES/EBU to S/PDIF, the CO3 must create SCMS bits (as
selected by the user) in the outgoing S/PDIF stream because the source
AES/EBU stream did not include them. With this said, let’s go over the four
SCMS modes and how they behave in each situation.
SCMS "Pass-Thru" Mode
Pass-Thru mode merely passes all SCMS information received at the input