Hardware Reference
In-Depth Information
interface, the PC industry as a whole is slowly moving to DisplayPort as the replacement for DVI.
Many cards feature both DVI and DisplayPort ports, or HDMI and DisplayPort ports.
DMS-59
DMS-59 is a 59-pin connection used by some video cards. It was used by the initial implementation
of the ATI (later AMD) Crossfire's master video cards. Later, ATI and all AMD implementations
replaced the DMS-59 cable with an internal bridge card.
More recently, DMS-59 has been used along with a DMS-59 to dual VGA cable or DMS-59 to dual
DVI single-link cable to provide dual display support. Cards that use DMS-59 are sold as OEM
products and not at retail. A DMS-59 connection is the same size as DVI but contains 59 smaller pins.
HDMI
HDMI was designed by a group of multimedia companies (Hitachi, Panasonic, Philips, Silicon
Image, Sony, Thomson, and Toshiba) as a way to provide a single-cable connection for transporting
digital video and audio signals between consumer electronics hardware such as big-screen TVs,
video games, DVD players, and home theater systems. HDMI was introduced in December 2002,
version 1.3a was introduced in November 2006, version 1.4 was introduced in June 2009, and
version 1.4a was introduced in March 2010. HDMI 1.4b was released October 11, 2011. Shortly
after that, the HDMI Forum was created on October 25, 2011 to develop all future HDMI version
specifications. HDMI is basically a superset of DVI and uses the same TMDS (Transition Minimized
Differential Signaling) as does DVI. Unlike DVI, however, each color channel also carries
multiplexed audio data. HDMI 1.2a and earlier supports a maximum data clock rate of 165MHz,
sending 10 bits per cycle, or 1.65Gbps per channel. There are three channels per link, resulting in a
maximum raw bandwidth of 4.95Gbps. Because the data is sent using 8b/10b encoding, only 8 bits of
every 10 are actual data, resulting in a true data throughput of 3.96Gbps. This enables a single-link
HDMI 1.2a or earlier connection to easily handle computer video resolutions as high as WUXGA
(1920×1200) as well as 1080p HDTV (192×1080 with progressive scan) plus audio data.
HDMI 1.3 increases the maximum clock rate to 340MHz, resulting in 10.2Gbps raw bandwidth, or a
true data throughput of 8.16Gbps. This increase allows a single-link HDMI connection to have
slightly more throughput than a dual-link DVI connection, which handles computer resolutions as high
as WQUXGA (3840×2400) plus audio data.
HDMI 1.4 adds support for Ethernet connections through the HDMI cable, audio return, 3D Blu-ray
video playback, all current as well as future resolutions up to 4096×2160, better color spaces
support, a micro-HDMI connector, new cable standards, and support for automotive connectors.
HDMI 1.4 also introduces cable speed and feature categories: Standard (up to 1080i), High Speed
(1080p), Standard HDMI with Ethernet, High Speed HDMI with Ethernet.
HDMI 1.4a adds support for new side-by-side and top-and-bottom 3D broadcast standards.
HDMI 1.4b adds support for 1080p video at 120Hz.
HDMI can also carry up to eight channels of uncompressed digital audio at 24-bit/192KHz along with
Dolby Digital, DTS, Dolby TrueHD, and DTS-HD Master Audio compressed audio formats. Because
it uses a single cable for both audio and video signals, HDMI provides an excellent way to reduce the
cabling tangle present in home theater systems that use conventional analog audio and video cables.
For home theater users who subscribe to HDTV satellite or cable services, HDMI is ideal because it
supports high-bandwidth digital content protection (HDCP), which these services use to protect
content from piracy while still assuring high-quality viewing and listening. To avoid reduced-quality
