Tag Archives: MHL

What is the MHL Specification?

A present, we are inundated with a plethora of digital devices. For example, we have set-top boxes or STBs, Blu-ray players, AVRs, automobile information systems, monitors, TVs, tablets, smartphones and others making up this large and diverse ecosystem. For getting all these to plug-and-play together is no mean feat and the latest standard connector that manufacturers are adopting for compatibility is the USB Type-C.

The protocol that the USB Type-C will be using for the delivery of audio, video, data and power is the MHL Alt Mode for the superMHL and MHL 1, 2 and 3 specifications. MHL Alt Mode over USB Type-C will allow interconnections of more than 750 million MHL devices. With USB Type-C, you can never plug-in a device in the wrong way – this is a reversible connector.

Backward compatible with USB 2.0 and USB 3.1, both Gen 1 and Gen 2, MHL Alt Mode for USB Type-C features power charging and Immersive audio such as DTS:X, Dolby Digital, Dolby Atmos and more. It allows transmission of 4K data at 60fps over a single lane or 8K data at 60fps over 4 lanes. You can use your existing remote to control existing MHL phones, as there is backward compatibility with existing MHL specifications.

The MHL Consortium has developed and published the MHL Alternate Mode for the superMHL and MHL 1, 2 and 3 specifications. They have established a liaison with the USB-IF and USB 3.0 Promotion Group for obtaining the official SVID and for ensuring the development of the specification confirms to USB Type-C, USB Billboard and USB Power Delivery specifications.

MHL Alt Mode over USB Type-C presents a single, small form factor connector, an ideal for many devices for delivering audio, video, data and power. You can simultaneously charge your smartphone, tablet or notebook when you connect them with larger displays such as car information systems, projectors, monitors and TVs
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You will know your USB Type-C port on your host and device supports MHL if you see the USB-IF logo near the port. Smartphones and tablets with the MHL Alt Mode can easily connect to existing car infotainment systems, projectors, monitors and TVs. With MHL cables and MHL-to-HDMI adapters supporting USB Type-C, you can connect to HDMI Type A devices as well. For this, you will need a simple, thin MHL cable that has an HDMI Type A connector on one end and a USB Type-C connector on the other.

A user can use his existing TV remote to control the device as the MHL Alt Mode supports Remote Control Protocol as well. In contrast, an alternative technology DisplayPort from MPEG-LA does not offer the same compatibility. With the DisplayPort Alt Mode, the user would have to actually go to the connected device and manually control it.

Protocol adapters for the DisplayPort Alt Mode will not work for the MHL Alt Mode and vice-versa. Manufacturers will have to use proper labeling to identify DP Alt Mode or MHL Alt Mode on adapters to avoid consumers from being confused. Proper protocol adapters are necessary for the MHL Alt Mode to support VGA, DVI and HDMI displays.