What is MHL Cable and why should you need?

The first time we saw what looked like an extra HDMI port on a TV that was was labeled "MHL," we said, "Awesome!" Then we wondered, what the heck is MHL Cable? Think of it as a technology that turns a common MicroUSB cable into an HDMI cable, but with a few special features.
MHL stands for Mobile High-definition Link, and it's the brainchild of a group of companies—including Nokia, Samsung, Silicon Image, Sony and Toshiba—that wanted a specification that could be used to connect smart phones, tablets, and other devices to an HDTV. As you'd expect, MHL supports 1080p video as well as 7.1-channel digital multi-channel audio, so it's an easy way to send high-def videos from your portable device to your big-screen TV. Great, you might say, but can't we already do that wirelessly?
Yes, but MHL adds a few cool new tricks. One is that it sends control data through the same cable, so you can control the portable device using your TV's remote. The other is that the cable provides power, so you won't drain your portable device's battery while the media is playing.
If you have a smart phone that supports MHL (and many newer phones, such as the HTC EVO 4G LTE and Samsung Galaxy S III do) and an MHL-supported TV, then the quickest route to trying this new technology is to get an MHL adapter cable, which has a MicroUSB connector on one side and an HMDI slot on the other. Just connect the MicroUSB connector to your phone, then run an HDMI cable from your TV's input to the HDMI slot on the adapter. No additional gear is needed.
But even if you don't have an MHL-enabled TV, you can still watch content from your phone. Many MHL adapters have an additional port where you can plug in your portable device's Micro Usb HDMI Adapter so it won't power down. (Some may use a separate charging dongle attached to the adapter.) But you likely won't get the remote-control functionality.
In addition to MHL-enabled smart phones, we're starting to see a growing number of other types of MHL-enabled devices, including TVs from Insignia (Best Buy), LG, Samsung, Sharp and Toshiba. And we also just tested the first MHL-enabled Blu-ray players we've seen, from Sharp.