Guntermann & Drunck DL-Vision(M/S) - Handbuch (Seite 108)

Background information
42 · G&D DL-Vision(M/S)
Background information
Support of any graphics resolutions
The KVM extender basically supports all resolutions that can be transmitted accord-
ing to the 1.0 DVI specification. This restriction mainly affects the pixel rate, which
can reach from 25 MHz (single link) to 165 MHz (dual link) or from 165 to 330 MHz.
During single link operation, the common VESA DMT and VESA SMT timing
standards enable resolutions between 640 × 480 pixels at 60 Hz and 1600 × 1200 pix-
els at 60 Hz.
1920 × 1200 pixels at 60 Hz are transmitted according to VESA CVT-RB, 1920 × 1080
pixels at 60 Hz (progressive) are transmitted according to CEA861.
Among other resolutions, dual link operation additionally supports the resolutions
2560 × 1600, 2048 × 2048 and 1920 × 2160 pixels (each at 60 Hz) according to
VESA CVT-RB.
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 video data that are transmitted from the computer to the computer module
( DL-Vision-CPU ) are transferred to the monitor of the remote console. The signal’s fre-
quency and display position at the computer module therefore correspond to those
of the graphics output.
DDC transmission with cache function
The KVM 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 reso-
lution and the supported monitor frequencies.
In order that the computer connected to the computer module ( DL-Vision-CPU ) can
already access the features of the remote monitor during booting, the KVM extender
contains 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 connected monitor or a default data block are provided in the KVM
extender.
The monitor’s DDC information is usually transmitted one-to-one to the computer.
In case, the KVM extender determines that the display cannot be read without
errors or that the entries are invalid, the information is completed or corrected (if
possible).