MMX6x2-HT
User’s Manual
Section 3. Technologies Page 15 / 119
3. Technologies
3.1. Understanding EDID
EDID stands for Extended Display Identification Data. Simply put, EDID is the passport of
display devices (monitors, TV sets, projectors). It contains information about the display’s
capabilities, such as supported resolutions, refresh rates (these are called Detailed
Timings), the type and manufacturer of the display device, etc.
After connecting a DVI source to a DVI display, the source reads out the EDID to determine
the resolution and refresh rate of the image to be transmitted.
Figure 3-1. EDID communication
Most DVI computer displays have 128-byte long EDID structure. However, Digital
Televisions and HDMI capable displays may have another 128 bytes, which is called E-
EDID and defined by CEA (Consumer Electronics Association). This extension contains
information about additional Detailed Timings, audio capabilities, speaker allocation and
HDMI capabilities. It is important to know, that all HDMI capable devices must have CEA
extension, but not all devices are HDMI capable which have the extension.
3.2. Common problems related to EDID
Problem: „My system consists of the following: a computer, a Lightware MMX6x2-HT
matrix and a third party Distribution Amplifier, then an SXGA (1280x1024)
LCD monitor and an XGA (1024x768) projector. I would like to see the same
image on the monitor and the projector. What EDID should I choose on the
matrix?”
Solution: If you want to see the image on both displays, you need to select the resolution
of the smaller display (in this case XGA); otherwise the smaller display may
not show the higher resolution image.
Problem: „I have changed the EDID on an input to have a different resolution but nothing
happens.”
Solution: Some graphics cards and video sources read out the EDID only after power-
up and later they don’t sense that EDID has been changed. You need to
restart your source to make it read out the EDID again.
Problem: „I have an MMX6x2-HT220 and I’m using a Lightware factory preset EDID. I
would like to be able to choose from different resolutions, but my source allows
only one resolution.”
Solution: Most Lightware factory preset EDIDs allow only one resolution, forcing the
sources to output only that particular signal. You need to select a Universal
EDID. It supports all common VESA resolutions. Additionally, it also features
audio support.
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