What is HDMI?
HDMI (High-Definition Multimedia Interface) is an industry-supported, uncompressed, all-digital audio/video interface. By delivering highest-quality all digital audio and video signals over a single cable, HDMI dramatically simplifies cabling and helps reduce the cost, complexity, and confusion of multiple cables currently used in A/V systems. Because HDMI is a digital interface, it provides the best quality of video by eliminating the need for lossy analog to digital conversions. This is particularly noticeable at higher resolutions such as 1080p.
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Is HDMI backward compatible with DVI (Digital Visual Interface)?
Yes, HDMI is fully compliant with DVI compliant devices. HDMI is the only interface enabling connections to both HDTVs and digital PC monitors implementing the DVI and HDMI standards.
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What functionality was added with the HDMI 1.3 specification?
HDMI version 1.3 was released in June of 2006. HDMI 1.3 increased its single-link bandwidth to 340 MHz (10.2 Gbps) to support higher resolutions, Deep Color, and high frame rates. It introduced a new, smaller form factor mini connector to accommodate small portable devices such HD camcorders and still cameras. HDMI 1.3 incorporated automatic audio synching capabilities and added support for new lossless compressed digital audio formats (Dolby TrueHD and DTS-HD Master Audio).
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What version of HDMI do I need to view 1080p content?
HDMI has always supported 1080p resolution, starting from version 1.0 in 2002. However, it is up to the device manufacturer to choose whether to implement 1080p support in the device. Viewing 1080p resolution requires at minimum that the HDTV have a display supporting the 1080p pixel resolution. A large number of display devices (LCD, PDP, etc.) in use today were designed for 720p pixel resolution, mainly due to cost. But as prices are trending down, more and more manufacturers are producing HDTVs with full 1080p support.

All versions of HDMI are backward compatible. Consumers should not look for a particular version of HDMI, but rather for the functionality that they want the device to support (SACD, 1080p, etc.).
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Does an HDMI accessory device (i.e. switch box, cable booster) need a dedicated power supply to work?
The answer is usually No. The HDMI specification requires all source devices to provide at least 55mA on the 5V line of the HDMI connector. While 55mA is not enough current to operate most HDMI access devices (typically need about 100-150mA), most source devices on the market today provide significantly more current on the 5V line than the HDMI specification requires. As a result, the vast majority of accessory devices can operate without an external power source when interfaced with a source device that provides over 100-150mA.
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How long can an HDMI cable be?
HDMI was designed to use a standard copper cable but it does not specify a maximum cable length. In general, the better the cable construction the further the distance it can carry the signal. But it is important to note that it is not only the cable that factors into how long a cable can successfully carry an HDMI signal, the receiver chip inside the TV or projector also plays a major factor. Receiver chips that include a feature called “cable equalization” are able to compensate for weaker signals thereby extending the potential length of any cable that is used with that device. You can also use a repeater to regenerate the signal and effectively extend the distance of a cable. We recommend using at least 28AWG cables for shorter distances up to 10m (about 33 feet), and thicker 24AWG cables for anything above 10m.
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Can HDMI cables contribute to devices not working together properly?
It is fairly rare for a cable to be the cause of HDMI compatibility problems. The vast majority of image quality or interoperability issues with HDMI devices are related to the software (firmware) used for device communication and content protection, and have nothing to do with the HDMI cable. In particular, these issues are often caused by the software related to HDCP handshaking, or from devices improperly handling the device capability information read through HDMI.
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What is the difference between a Standard HDMI cable and a High-Speed HDMI cable?
Standard (or category 1) cables are tested to perform at speeds of 75MHz (equivalent to 1080i signal). High-Speed (or category 2) cables are tested to perform at speeds of 340MHz and can successfully handle 1080p signals as well as higher resolution displays.
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Will my Standard cable work in high speed applications?
Although Standard cables may have not been tested for higher bandwidths, they will generally perform adequately in higher speed situations, especially ones of shorter lengths (i.e. less than 2 meters). The vast majority of HDMI TVs and displays that support 1080p are designed with quality receiver chips that are able to cleanly recover the 1080p HDMI signal using a Standard rated cable. However, if you are looking to purchase a new cable it would be best to chose one that has been tested at the higher speeds.
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What is HDCP?
HDCP (High-bandwidth Digital Content Protection) is a technology developed to help protect digital entertainment content. HDCP has been implemented across both DVI and HDMI interfaces. HDCP gives content owners (e.g. movie studios) the ability to protect their HD content against unauthorized copying. If you want to be able to play high-definition content you should ensure that your HDTV and other HD devices are able to support HDCP-encrypted content.
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