M-Audio CO3 [5/8] Advanced information

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