Barco TransForm SCN, User Manual, Page: 25 / 61

4. Operating
Barco – TransForm SCN – R5976968 – Revision 01 – May 2006
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4-2
4.1 Encoder
4.1.1 Encoding
A digital or analog graphical source up to UXGA@60 Hz is connected to the graphical input of the encoder.
The encoder detects the source and, if recognized, automatically adjusts the necessary parameters. In this way
no manual adaptation is necessary when the source changes.
4.1.2 DDC
The Display Data Channel or DDC is a digital connection between a computer display and a graphics adapter that
allows the display to communicate its specifications to the adapter.
The T
RANS
F
ORM
SCN provides DDC data at the input connector for the host PC which creates the image. This DDC
data is in general looped through from the monitor. If a monitor gets connected to the T
RANS
F
ORM
SCN while the
T
RANS
F
ORM
SCN is already in operation, the host PC will not adapt its output timing for this monitor. For this case
or for monitors without DDC capability an upper limit for the timing can be set and can be sent from the
T
RANS
F
ORM
SCN instead of looped through DDC data to the host PC. The upper limit can also be used to optimize
bandwidth usage.
The table below shows which setting is used in which situation:
incoming DDC at output connector DDC at input connector
incoming monitor DDC ≤ upper limit DDC monitor DDC
incoming monitor DDC
>
upper limit DDC upper limit DDC
monitor without DDC upper limit DDC
no monitor connected upper limit DDC
Figure 4-1
DDC – operating mode
Anyhow for decoding the detected timing the parameters of the source are used, not the DDC information, en-
suring that also graphical sources of systems which are not DDC compliant are optimally decoded.
The maximum DDC timing is set by means of the T
RANS
F
ORM
SCN web interface, please refer to section 4.3.7
Encoder settings – timing .
4.1.3 Loop through
The graphical output port is an active loop through of the graphical input with sync recovery. The table below
shows which output signal is provided on basis of the provided input:
input signal output signal
analog analog and digital simultaneously
digital digital
Figure 4-2
loop through – format of input and output signal