The DisplayPort Information Guide
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An Introduction to the DisplayPort Interface
WHAT IS THE DISPLAYPORT CONNECTOR?
DisplayPort is the newest digital video interface connect,
designed as a replacement for the DVI standard currently in use on computer
hardware. It is similar in specification to the HDMI standard, but
unlike HDMI, DisplayPort is being targeted as a computer-interface more than
HOW IS THE DISPLAYPORT DIFFERENT FROM VGA AND DVI?
While VGA has served the computer industry well for many years, its
analog-based signals (frequency-modulated red, green, and blue components)
are a weakness in fidelity. The digitally-rendered signal must be converted
to analog by the video card, which adds inconsistencies and blending, and
identical source images can vary greatly on different displays, depending on
the displays' subjective calibrations.
DVI and DisplayPort are both digital-only signals, which ensures that the
final image displayed is identical to the image rendered by the computing
hardware. Excluding DVI's existing dominance in the market, DisplayPort
has a number of advantages over its predecessor:
Unfortunately, DisplayPort and DVI use fundamentally different signal processing
methods, so adapting between the two cannot be done with a simple adaptor or
cable (in most circumstances). DVI, like VGA and HDMI, uses separate data channels
for each color, requiring a high bandwidth at all times. DisplayPort renders
the entire image and breaks it into packets, and these are transferred to
the display much like network data over an ethernet line.
Some DisplayPort ports are built to be
compatible with DVI internally, and can be adapted passively, but this is
not a requirement of the DisplayPort standard. In these situations it will appear
as though the Displayport is being "converted" to DVI, but it's actually the hardware
outputting a DVI signal through a Displayport connector. If the hardware in use
is not capable of outputting this DVI signal, then a Displayport-to-DVI adaptor
will not function properly.
- The DisplayPort connector is small and screwless, for easier
installation, and added usability in space-conscious hardware
- DVI offers no audio support; DisplayPort offers full digital audio
support (up to eight channels) in the same cable as video
- DVI is crippled by its maximum spec length of 5 meters, while
DisplayPort is designed for up to 15 meters.
HOW DOES DISPLAYPORT COMPARE TO HDMI?
While HDMI is the digital standard targeted towards home theaters and Displayport
targeted towards computer electronics, DisplayPort touts a feature-list virtually identical to
HDMI. In fact, the DisplayPort 1.1 standard was adjusted to specifically
include the HDCP content-protection standard, to improve compatibility with
Because DisplayPort has a newer release schedule than HDMI, it does outperform
in a handful of specifications:
- It has a maximum bandwith of 10.8 Gbit/sec, compared to HDMI at 10.2
- It supports the DPCP (DisplayPort Content Protection) standard in
addition to HDCP
- It is an open standard, available to all manufacturers at no cost; HDMI
is licensed by HDMI LLC, which raises the cost to manufacturers and consumers
IS DISPLAYPORT COMPATIBLE WITH VGA, DVI, AND HDMI?
VGA and DisplayPort - Unfortunately VGA supports only analog-based
signals, and DisplayPort only digital-based. A conversion from VGA to
DisplayPort (or vice versa) will require an electronic convertor, much like
today's VGA to DVI-D units.
DVI and DisplayPort - Aside from DVI's lack of audio support, the two
interfaces are somewhat compatible. DisplayPort uses a signal technology
entirely different from DVI/HDMI, and is not natively compatible. However,
some DisplayPort hardware has built-in convertors to a DVI-compatible
format, so a passive DVI/HDMI adaptor will function properly. If the
DisplayPort does not have this feature, then external electronic conversion
will be necessary.
HDMI and DisplayPort - DVI and HDMI use the same signal technology,
so HDMI suffers the same incompatibility with DisplayPort, and likewise the
same possibility for conversion. If the DisplayPort hardware has built-in adaption, then a
DisplayPort-to-HDMI cable or adapter will function perfectly. If not, then
an external HDMI-DisplayPort convertor will be necessary.
WHERE IS DISPLAYPORT AVAILABLE?
Since 2008, DisplayPort has been slowly integrated into consumer electronics
and can be found on most high-end flatpanel displays and modern video cards.
Consistent with its emphasis on the computer market, DisplayPort is less
commonly found on Blu-Ray players and set-top boxes, although such can be found.
Written by Anthony van Winkle
for DataPro International Inc.|
Unauthorized duplication strictly prohibited.