Wireless Headphones, Fitness bands, Bluetooth Speakers, In-Ear headphones, Mobile phones, Laptops… there are so many Bluetooth devices around us and most of these devices are battery operated. Have you ever wondered that, when you connect a Bluetooth device to your mobile phone how it automatically understands that the connected device is a computer or audio device or a mobile phone? For some devices our phone might even automatically shows the battery percentage of the connected device on the notification bar. How does all this happen on their own? There should be some common protocol shared between the phone and the Bluetooth device right!