ClearOne Digital Media - Manual (Page 32)

Q. Can HDMI cables contribute to devices not working properly together?
The vast majority of image quality or interoperability issues with HDMI devices are related
to the software (firmware) used for device communication and content protection (HDCP),
and have nothing to do with the HDMI cable. These issues are often caused by the software
related to HDCP handshaking, or from devices improperly handling the device capability
information read through HDMI (EDID is incorrect). It is fairly uncommon for the cable to be
the cause of HDMI compatibility problems, generally the issues are HDCP related when a
source will not properly talk to a display.
Q: Is it possible for a source to connect to more sink devices (displays)
then it supports?
The answer to this question is “No”. It is not possible to achieve this unless a product is
infringing on the HDCP license due to improper implementation. This is a question of great
confusion for dealers due to a few well-known HDMI matrix switcher products not properly
implementing HDCP.
The reason this is not possible is because HDCP is a technology designed for point to point
content protection to ensure high value data transmitted digitally from a source to a display
is fully protected and not easily hijacked or stolen in route.
HDCP works by allowing every source device to accept a fixed number of keys that allow it
to support one or more display devices or “sinks” based on the number of keys the source
product supports. As an example, there are several popular cable set-top-boxes that only
support a single display device. For the A/V systems design professional and installer this
can be problematic where the client may desire the source be simultaneously displayed
on a projector and flat panel display. This is not possible if the number of display devices
exceeds the key count contained in the source.
To ensure your projects do not run afoul of HDCP licensing and implementation rules
all StreamNet products implement HDCP as specified in the Digital CP agreement. We
encourage you to not submit your company or client to legal scrutiny by using products
which do not fully or properly implement HDCP.
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pg 32 StreamNet Digital Media and System Design Reference Guide
HDCP Quick FAQ