MHL technology: what is it?

Today mobile devices in the form of smartphones and tablets are becoming more and more "smart", and many of them in their functionality are not inferior even to powerful computer systems. And, interestingly, the new devices mostly support the MHL technology. What is it, now and see. At the same time, we will determine the main points concerning the connection of gadgets to TV panels and the appropriateness of using such innovations.

MHL technology: what is it?

In general, the abbreviation MHL stands for Mobile High-Definition Link (almost HDMI), which, in conventional terms, can be interpreted as a technology for mirroring the screen of a mobile device on a high-resolution TV panel.

It appeared relatively recently, so even declared support for MHL in some devices may not work. To date, the most common and used are MHL-versions 1.x and 2.x, and only recently appeared the third version, which, although it has quite high prospects for implementation, has not yet received wide distribution.

As for the main features, the use of such a screen duplication technology allows from the mobile gadget to transmit to the TV panel an image of the Full HD format with a resolution of 1080p and surround sound of the standard 7.1 with minimal delays in the transmission time. But this applies only to the first and second versions. In the third modification, to the surprise of many, the ability to broadcast images in 4k (Ultra HD) format was added.

Analogues of MHL

If you consider some similar developments, it is easy to see that this technology is very much like, say, Miracast or Intel WiDi. In mobile devices and panels Samsung MHL is often referred to as Screen Mirroring. This is wrong, although there is an analogy.

However, similarity in our case concerns only the principles of signal transmission, and certainly not connectivity. Hence - and the fundamental differences in the basic principles that correspond to the use of MHL in practice.

The main differences between MHL and other standards

Now let's look at the well-known developments and the original MHL technology. That this is by its principle of connection, it is easy to understand, given that the broadcast is carried out exclusively using a wired connection type of HDMI, and not using, for example, Wi-Fi connections.

In other words, in order to transfer the image from the mobile device to the TV panel, you need to use special cables with adapters. It is in this new technology is very much similar to the usual connection via an HDMI cable.

But! If the mobile device is connected via either the HDMI connector or use a wireless connection, it will be discharged fairly quickly when the signal is broadcast. But MHL allows you to connect and still charge the device as it happens through the connection to USB-ports. Here, too, there may be two options: either charging is done using an external source, or from the panel itself. It all depends on the type of adapter used. In addition, it is the connection of special adapters that makes it possible to broadcast the signal even if the MHL technology is not supported by any of the devices. And this is a weighty plus.

How to connect via MHL-adapter

As already mentioned, for proper connection, you should use special adapters. They are divided into two main types: passive and active.

Passive cable is very similar to standard cords for mobile devices. On the one hand there is a micro-USB connector, on the other - a plug resembling a normal USB. In fact, the second connector is a standard MHL-connector and must be connected to the TV-panel via a special socket.

If there is no such slot on the panel, it makes sense to use a passive cable that has the same micro-USB connector and two more ports: HDMI (MHL) and a standard micro-USB input.

As for charging gadgets, in the first case, a direct connection to the TV is used, in the second variant it is supposed to connect an additional external source (remember how passive and active speakers work for computers). Incidentally, it is the presence of a passive cable that allows broadcasting on panels in which MHL-support is not available.

All pro and contra

So we got to know a bit about MHL technology. What it is and why it is needed, I think, is already a little clear. Now let's look at some of its advantages and disadvantages.

Undoubtedly, support for high-definition images (up to 4k), Dolby Surround 7.1 and DTS sound, and the possibility of using multiple monitors at the same time, plus the connection of a sufficiently large number of supported peripheral devices (mouse, keyboard, touch screens etc.). In addition, the technology itself is based on the basic principle of self-adjusting Plug & Play devices, that is, you do not need to make any settings - plug and use.

As for the shortcomings, the main problem here is that today there are a limited number of both mobile gadgets and TV panels that support MHL (about version 3.0 and in general it is not necessary to speak). Thus, most tests show that at best, a 1080p image with a frame rate of about 50 fps can be transmitted. When trying to broadcast more video with a smoother transition at 60 fps, alas, very often there are problems. Finally, the current in 500 mA, provided in version 1.0, is not enough for a full charge of the mobile device.

What in the end?

Here, perhaps, and all on the topic "MHL: what is this?" Of course, here are given only the main aspects associated with the technology itself, the principles of its use and practical application without in-depth study of the technical part of the issue. Nevertheless, it seems, even such brief information can give an idea of how much such a technology is promising, despite even a wired connection between devices. Naturally, I would like to hope that the developers will not stop there and present to the world some innovative development on this basis, especially since wireless chargers are no longer a wonder. It was interesting to look at the combination of such charging with wireless image transmission ...