The very small USB port found on many non-Apple cellphones, tablets and other portable devices is a Micro USB socket.Considerably smaller than USB Type A and B, Micro USB is also half the thickness of Mini USB (see illustration below).One reason is that the pin assignments are symmetrical, a fact that becomes evident by examining the pin assignments on a type C connector.
USB Type-C connector and cable is reversible (the connector has no “up” side) and the cable is reversible (either end can plug into any device).
The spec also provides more internal wiring than USB 3.1 strictly needs, allowing it to work with other standards such as Display Port.
The current version of the standard, USB 3.1, extends the performance range to 1 GB/sec.
Another point to note about speed is that USB 3.0 ushered in “Super Speed” 5 Gbps, and the USB 3.1 maximum rate of 10 Gbps is called “Super Speed Plus.” USB 3.1 peripherals share bandwidth through a protocol that lets peripherals be attached, configured, used, and detached while the host and other peripherals are in operation.
USB 3.1 also provides backward compatibility with USB 2.0 by means of a dual-bus architecture: One bus is a USB 2.0 bus while the other is an Enhanced Super Speed bus.
The USB 3.1 spec uses the term Enhanced Super Speed as a generic adjective referring to any valid collection of USB features that were defined for the bus that runs in parallel to the USB 2.0 bus in a USB 3.1 system.
Developed by Qualcomm, it aims to charge batteries in a way that is more energy efficient than ordinary trickle-charge setups. “It is difficult for suppliers of USB connectors to differentiate themselves,” says CUI Inc. “One way we compete is by providing a broader range of mounting options, including a water-proof version we have in the works.” However, one differentiating feature that USB specifiers should indeed watch out for are connector markings that indicate certification, says Carroll.
Set up by the USB Implementers Forum, a compliance program uses a test regime at third-party testing organizations that is designed to signify a certain level of quality.
Standard USB B devices can connect to USB 2.0 hosts through a USB 2.0 A-to-B cable, which is compatible with USB 3.0 B ports.
Powered USB devices, though, have a non-removable, hard-wired cable.