Compaq dc7900 An Overview of Current Display Interfaces - Page 9

HDMI After the DDWG failed to agree on a specification for a consumer version of the DVI specification, Silicon Image formed a new consortium to develop a digital interface specifically for the consumer TV market, this time with six leading CE companies. The result was the High Definition Multimedia Interface, or HDMI. HDMI is essentially a single link of the TMDS electrical interface (as used in the DVI standard), plus a standard (and Silicon Image proprietary) method of carrying digital audio signals within the video data stream. Like DVI, HDMI also supports the Intel High Definition Content Protection (HDCP) copy-protection scheme. As in DVI, HDCP support is technically optional, but basically required for products in the CE market and HDMI implementations. HDMI is semi-compatible with single-link DVI, as DVI cannot provide the embedded audio features of HDMI and does not support HDMI's Consumer Electronics Control (CEC) channel, a one-line serial data bus for the control of CE products (such as DVD players, etc.) from the TV or other output device. As was the case with DVI, HDMI (up to the 1.2 specification revision) provides support for up to 165 MHz pixel rates, or about 4.8 Gbit/sec. raw data capacity. The HDMI 1.3 spec is intended to approximately double this capacity, although it is unlikely that existing HDMI cables, etc., will support the higher rates. HDMI 1.3 also introduced a more compact version of the connector, for portable CE products, the HDMIC. The HDMI specification also includes a dual-link version, the HDMI-B connector, intended for PC use, but it has never been adopted by the PC industry. At this point PC usage of HDMI is limited to the HDMI-A, and then primarily for CE-connectivity purposes. Figure 6 HDMI Receptacle 9