Avocent Emerge MPX Installer/User Manual page 91

• Initiate a video hot plug of the source and display devices to ensure that the EDID infor-
mation has been read and transferred across the extension network.
• Power cycle the transmitter to clear invalid HDCP keys, which may have been collected
from a non-valid display device. An invalid key will prevent the transmitter from sending
protected content.
• Determine if you are sending protected content. If so, do all of the display devices have
appropriate content protection keys?
• If only one display is not working, try making it the primary. Perform a hotplug of the
video connection (HDMI, VGA). If the problem is resolved and the displays are different
models, there may be a incompatibility between the options these monitors support.
Motion video is choppy: This is an indication that frames are being dropped. "Fine tuning
suggestions" on page 47 provides steps to resolve this issue.
Additional tips for VGA display devices
Display devices differ widely in their support of video resolution, refresh rates, color depth and
other configurable features. To allow source and display devices to negotiate available settings in a
plug-and-play manner, a display data channel standard has been adopted by the industry. The
standard supported by MPX extenders is DDC2B. This standard is adhered to by most VGA, DVI,
and HDMI display devices. Compliant display devices contain a PROM that can be read by a
source device across a display data channel (DDC). The PROM contains formatted information
about the capabilities of the display. This information is commonly referred to as extended display
information data, or EDID string for short.
DVI-D and HDMI source devices will dynamically query this information when a display device
hot-plug event is detected. Thus, displays are immediately available. Most VGA computer source
devices such as graphics cards, however, query information only once, upon power up. For this
reason it is particularly important that EDID information is passed through the extension network
and assembled by the transmitter into the Active EDID string before power up of VGA source
device. Therefore, the power sequence of MPX extenders, display devices, and source device
is critical when using a VGA source device.
NOTE: EDID information is maintained by the MPX transmitter in non-volatile storage; thus, the order of power
up sequencing is important only during initial installation.
If you followed the recommended power up procedure and no video is visible at the display device,
then the following tips may help you to resolve your problem.
• The VGA source may be operating at a resolution not supported by the MPX transmitter.
• If you are on a laptop, toggle the video back to the laptop display and check the resolution
of the secondary monitor. To test the connection between the transmitter and the receiver,
change the secondary monitor setting to 640 x 480 @ 60Hz resolution. Again, toggle the
video to the VGA connector. Video should appear within 30 seconds.
Appendices 77