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.
Overview of USB Ports: A USB port is a standard cable connection interface on personal computers and consumer electronics. USB ports allow stand-alone electronic devices to be connected via cables to a computer (or to each other).USB stands for Universal Serial Bus, an industry standard for short-distance digital data communications.f using a USB hub, plug a separate cable into each device and connect them to the hub individually. You may plug cables into a USB port at any time regardless of whether the devices involved are powered on or off.