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GrandTec USB to HDMI Adapter



You've probably seen a coworker or colleague using multiple LCD monitors at their computer workstation.  Research at the University of Utah indicates that the use of multiple monitors can significantly improve worker productivity.   It has been possible to integrate multiple monitors if the computer had DVI or HDMI outputs, but computers equipped with this functionality are still rare.  Currently less than 2 percent of workstations are equipped with more than a single monitor.  There is a need for a simpler solution.


A new USB-HDMI adapter module has been introduced recently that should help. The Grandtec Electronic "Grand HD Cinema" (GHD-2000) adapts a USB port for use as an output for up to 6 monitors (4 for Mac).  This is also an easy way to implement an HDTV adapter for a laptop computer. This module is about the size of an AC adapter power supply for a laptop computer.  What makes this product different than its competitors is the integrated circuit chips and software drivers, the "Display Link" technology.

Demonstration of the GrandTec USG HDMI Applications.



Display Link Technology


The critical chips used are made by a company called DisplayLink (formerly Newnham Technology, website: displaylink.com).  The company is headquartered in Palo Alto, California, with research and product development in Cambridge, England.  DisplayLink is a fabless operation, so the manufacturing of the integrated circuits is probably performed in Taiwan. 


DisplayLink technology supports 32-bit color at all resolutions. Whenever native resolution can be detected, DisplayLink will display the native resolution of the screen automatically.  The video output format is capable of high definition (720p), and audio functions for a single channel are also integrated.  DisplayLink also provides much of the software for automatically configuring the video adapter and the USB port. 


DisplayLink compresses the video signal for transport over the USB link to improve bandwidth.  Video signals, especially HDTV signals, when uncompressed, require enormous bandwidth.  If the original signal source is encoded video (see MPEG) then the computer must first decode the signal. Then the DisplayLink software driver must compress the signal using the proprietary DisplayLink video compression codec.  This is basically transcoding, which is one of the reasons that the computer requirements are significant.  The compressed signal is then sent over the USB link to the adapter.


Once the signal is past the USB link, the converter uncompresses the signal for broadcast over the HDMI link.   HDMI is capable of communicating uncompressed HDTV signals.


There is some misleading information on-line that claims that this product is HDCP capable, which implies that the system is amongst other things, BluRay DVD compatible.  Currently DisplayLink technology is not HDCP compliant, since DisplayLink’s compression codec cannot manipulate encrypted packages. 


Fast moving images may stress the capability of this technology because of the throughput limitations of USB 2.0.



Computer Requirements


The minimum computer requirements for this application are an XP or Vista operating system with a Pentium 4 CPU or equivalent at 2.4GHz.  Minimum RAM memory requirement is 512 MB.  The converter module relies on the computer CPU to perform the video encoding. The product is Plug and play with included software, and should install quickly.


Power for the converter is supplied from the USB port, so an AC power supply is not required.   



Video Wall


It is possible to implement a "video wall" with up to 6 displays, but only a single audio channel can be used.  Each screen's picture can be independently rotated in increments of 90 degrees. 


The system supports extended desktop video (a single image split over multiple monitors) or mirror imaging (the same image displayed on multiple monitors).  A separate USB-HDMI adapter module will be required for each monitor in extended desktop mode. 


With multiple USB-HDMI adapters, each monitor can show separate programming.  The limitation will be the computers ability to encode each channel because the process is computation intensive.


Many people now use their computers to watch television and movies.   There is a need to be able to easily view the computer's signal on a larger HDTV.  The Grandtec Electronic Grand HD Cinema is well suited for this purpose.  The Grand HD Cinema currently sells on-line for $130-$150.









 About the Author:


Brian Bradshaw is an InfoComm Certified Technical Specialist (CTS), Microsoft Certified Technology Specialist (MCTS), and CompTIA A+ Computer Technologist.  Areas of expertise include Video, HDTV, Audio, Computation, SATCOM Systems, and Communications.

Website:  http://bradshaw-vacuum-technology.com/