The high-speed transmission of audio and video data using High-Definition Multimedia Interface (HDMI) connectors is the foundation of modern entertainment and communication devices. However, the technology is rapidly moving beyond televisions and computer monitors into many high-voltage applications.
HDMI connectors are an essential input-output (I/O) component in nearly every modern entertainment and communication device. These connectors connect everything from computer monitors to TVs and game consoles by passing uncompressed digital signals from suitable audio-video (A/V) sources to receivers and monitors.
Although originally developed for the commercial systems we find in our homes and workplaces, HDMI connectors have continued to evolve and have been modified by manufacturers over the years to ensure successful operational results in challenging environments. These include military, medical and aerospace applications where electrical connections must be robust and versatile.
service requirements
The HDMI connector was developed to help simplify existing connectors, namely Digital Visual Interface (DVI) and analog Red Green Blue (RGB) component cables. At the time, DVI connectors were known for problematic mating and unmating, which could damage the connector itself or the source. RGB cables have their own problems: because they break the source signal into three parts, interference often occurs, and the connections are not always secure. Therefore, HDMI cables are carefully designed to simplify the mating/unmating process and reduce the number of connectors required from three to one.
Manufacturers began developing HDMI cables in 2002, and there are now five different types to choose from: 19-pin Type-A is the standard and most widely used, found in nearly every TV and computer monitor. Type-B was introduced as the original standard in 2002, but was never used in products due to the introduction of HDMI 1.3, whose single-link speeds exceeded the older dual-link speeds. Type-C mini connectors are used in portable devices such as DSLR cameras and satellite navigation. Meanwhile, Type-D connectors were introduced for audio-visual connections in small portable devices, and Type-E was designed for high-speed data transfer in automotive applications.
Improved technology
For applications in harsh environments, the modification of the connector is as important as its type. Harsh Environment HDMI connectors can include a number of different modifications, such as IP-rated sealing against contaminants such as fluids and fine particulate matter. The housing can vary depending on the environment, and available options include metals (eg, copper alloys, nickel, and aluminum), thermoplastics, and fluoropolymers. For example, Sure-Seal HDMI connectors are rated IP67 to keep out dust, water, chemicals and other contaminants. They also feature copper alloy, gold-plated contacts and operate over a wide temperature range.
When using harsh environment HDMI connectors, overmolding and combining wires and connectors is an option as this reduces stress and ensures more reliable performance by protecting it from challenging environments. Using a coupling or locking mechanism helps maintain a secure connection even when blind-mate connections or vibrations are involved.
Applications in Harsh Environments
Since its creation, HDMI connectors have simplified interconnection for a variety of applications. Harsh environments include outdoor digital signage, vehicle displays, military avionics and even electronic flight bag applications. Factory automation and control, machine tools, robotics, building automation, and test and measurement are also examples.
Common to all of these applications is that HDMI connectors must be able to withstand heavy-duty use and exposure to chemicals, water, oil, and extreme temperatures. Typically, this means choosing connectors that meet MIL-SPEC or some UL rating.
