Crestron DM-RX1-1G Specifications download pdf (Page 14)

Crestron DigitalMedia™ Design Guide

10 Check website (www.crestron.com) for product availability

USB HID Switch

DigitalMedia lets you centralize all HD sources – not just television receivers and DVD changers, but also media servers,

computers, and even video game consoles. Built-in USB HID (Human Interface Device) signal routing allows USB HID

compatible keyboards, mice, and game controllers to be connected at each display location, extending their signals through to

the centralized equipment via USB HID ports provided on select switcher input cards.

EDID Format Management

Using HDMI provides a variety of video and audio formats to keep track of, and chances are not every device in a system

supports all of the same formats. In a typical one-room system, HDMI attempts to resolve this confusion using EDID. When two

HDMI devices are connected together, the receiving device (a display or surround sound processor) uses EDID to announce its

format capabilities to the source device (a TV tuner or video player), which in turn configures itself to output the most effective

format that both devices can support.

However, serious conflicts can arise in a facility filled with different displays and audio systems. For instance, a Blu-ray player

feeding a 1080p projector in the theater may restrict itself to a lower resolution, or even shut off completely, if someone

decides to view the same signal on the 32” TV in the bedroom. And, instead of listening to a 7.1 Dolby TrueHD format

supported by a high-end theater sound system, the listening experience may be limited to Dolby 5.1, or even stereo sound.

DigitalMedia uses EDID to prevent such conflicts, assessing the formats supported by each system device, and then allowing

the installer to assign compatible devices in logical arrangements. Conflicting combinations can be prohibited so only the

optimum signal formats get delivered to each display and audio system in the house. Refer to the EDID section on page 4.

QuickSwitch HD™ Technology

Many content providers are using a copy-protection scheme called HDCP to protect products against unauthorized copying. To

view HDCP encrypted content in full high-definition requires the source device to “authenticate” every display and signal

processor through an HDMI connection before delivering an output signal. This process occurs every time any HDMI signal is

switched, causing a complete loss of signal for up to 15 seconds whenever a new source or display is selected anywhere in

the house. Crestron QuickSwitch HD technology eliminates this issue by maintaining a constant HDCP connection with each

HDMI device in the system. By eliminating the need to re-authenticate each time a different source or display is selected,

QuickSwitch HD achieves very fast switching of HDMI signals.

HDCP Key Management

Another aspect to HDCP is its use of “keys” to manage the handshaking that occurs between any two devices. Every HDMI

source device has a limited number of supported downstream devices, as determined by the number of HDCP keys available.

The number of HDCP keys is rarely advertised or specified by the manufacturer or service provider, so without warning, the

source simply stops outputting a signal when connected to too many displays or processors.

To prevent such surprises, DigitalMedia switchers test the HDCP limits of each HDMI source, allowing the installer to configure

the system around any limitations, or substitute a different component.

CEC Signal Management

The primary objective of every Crestron system is to enable precisely the control desired for a seamless user experience.

To ensure this outcome, DM switchers intercept the CEC signals that many HDMI devices automatically generate, preventing

any unwanted commands from being executed – like a Blu-ray player attempting to turn off the video display when it gets

turned off, or a DVD player trying to pause the other players in the system when it is playing. Through proper CEC

management, DigitalMedia allows you to take control of each device as you like.

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Crestron DM-RX1-1G Specifications Page 14