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.
The Universal Serial Bus : How it Works and What it Does. USB is a system for connecting a wide range of peripherals to a computer, including pointing devices, displays, and data storage and communications products. Although not a relatively new development in personal computing, it has only recently gained popularity due to increasing software support.