1 Echocardiography (echo) is a painless test that uses sound waves to create pictures of your heart.  This test gives your doctor information about the size and shape of your heart and how well your heart's chambers and valves are working.
USB was designed to standardize the connection of computer peripherals (including keyboards, pointing devices, digital cameras, printers, portable media players, disk drives and network adapters) to personal computers, both to communicate and to supply electric power.
USB On-The-Go (Amazon link), or USB OTG, is essentially a female USB port that plugs into the Micro-USB port of a phone or tablet, allowing you to connect devices that use a standard USB 2.0 or 3.0 connection. In a nutshell, the adapter allows the Android device to be a USB host, powering and communicating with the connected device. Compatibility.