MHL Connector - What are they for and what's the difference between a Micro USB?

MHL Connector

With smartphones getting more and more complicated and more and more capable all the time, they have been becoming an increasingly important part of our lives. No longer are they merely a means of communication; for many, their smart phones are their personal information manager (PIM), media center and more.


Nevertheless, even with the computing power that is included in the average smart phone, they are limited in their utility by the size of their screen. Manufacturers have been dealing with this by making smart phones with larger and larger screens; but even so, practical limitations of portability and use limit the maximum size of the smartphone.


The obvious solution to this is to make it possible to connect the smartphone to a HDTV for media use. That allows the phone to provide the media for viewing, whether by streaming it off the internet or from its internal memory. The HDTV provides the larger screen to enjoy the high-definition image.


Essentially, that’s what the MHL connector is all about. Several smartphone manufacturers got together and realized the necessity of a means of connecting a smartphone to a HTDV. Since the installation of a HDMI connector into a smartphone was impractical, due to the size of the connector, the MHL connector was born.


The MHL connector looks just like a standard Micro USB connector. However, the specification isn’t really about the connector type; but rather about the data transmission capability and format that is used. The major concern in the development of this connection was the capability of using it to connect smartphones to HDMI televisions, so that HD video, with 7.1 surround sound could be transmitted between the two.


The other end of a typical MHL adapter is a standard HDMI connection. However, most HDTVs will have a separate connection for MHL. Although this connection looks the same, the electronics backing it up aren’t. For a MHL device to be connected to a standard HDMI input connection, an active adapter needs to be used.


Although the five pin Micro USB is the most common connector that is used for MHL, it is not the only one. The specification doesn’t actually make specific connector requirements, so other types of connectors can be used. Some manufacturers are using the USB 3.0 Micro connection, which contains 11 contacts, instead of the five contacts that the original USB 3.0 has.


The media transmission capability of MHL includes 1080p60 video, as well as surround sound 7.1. This is much more capability than the normal Micro USB 2.0 is capable of.


MHL adds additional functionality to the Micro USB as well. It provides the capability of powering the smartphone with up to 10 watts of power, from an external power supply. A standard USB power supply can be usesd. Many MHL adapter cables come with a USB connection for this purpose. This connection allows the smartphone to be powered and recharged while it is being used to transmit media to the HDTV.


Version 3.0 of MHL also adds the capability of controlling the smartphone or other MHL device from the HDTV or the HDTV remote control. With this, you can select media off of the smartphone via the HDTV’s remote, rather than having to access the smartphone directly.


New devices are being developed to expand the MHL capability, including DVD recorder/players which are MHL compatible. A MHL dongle has also been developed, allowing MHL communication wirelessly. We can be sure that other types of devices, such as surround sound speaker systems will be following shortly.

Rich Murphy