Guntermann & Drunck DVI-Extender-F - Handbuch (Seite 34)

Background information
13 · G&D DVI-Extender-F
Background information
Support of any graphics resolutions
The extender basically supports all resolutions that can be transmitted according to
the 1.0 DVI specification. This restriction mainly affects the pixel rate, which can
reach from 25 MHz to 165 MHz.
The common VESA DMT and VESA SMT timing standards enable resolutions
between 640 × 480 pixels at 60 Hz and 1600 × 1200 pixels at 60 Hz.
1920 × 1200 pixels at 60 Hz is transmitted according to VESA CVT-RB, 1920 × 1080
pixels at 60 Hz (progressive) are transmitted according to CEA861.
Almost any refresh rate and resolution within the technical constraints are possible.
The available display modes are largely dependent on the graphics card, the gra-
phics driver, the operating system and the connected monitor.
The image data which is transmitted from the computer to the transmitter is directly
transferred to the console monitor. The frequencies and image position of the signal
at the transmitter therefore comply with those at the graphics card output.
DDC transmission with cache function
The extender supports Enhanced-DDC (Enhanced Display Data Channel) to read out
the data from the monitor that is connected to the user module and transmit them to
the computer. This data includes information regarding the preferred resolution and
the supported monitor frequencies.
In order that the computer connected to the computer module (DVI-Extender-F-CPU)
can already access the features of the remote monitor during booting, the system con-
tains a cache function. Even if the computer module or the user module are switched
off or if the devices are not interconnected, the properties of the most recently con-
nected monitor or a default data block are provided in the extender.
The monitor’s DDC information is usually transmitted one-to-one to the computer.
In case, the extender determines that the display cannot be read without errors or
that the entries are invalid, the information is completed or corrected.