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The written USB 3.0 specification was released by Intel and its partners in August 2008. The first USB 3.0 controller chips were sampled by NEC in May 2009, [4] and the first products using the USB 3.0 specification arrived in January 2010. [5] USB 3.0 connectors are generally backward compatible, but include new wiring and full-duplex operation.
USB Battery Charging (BC) defines a charging port, which may be a charging downstream port (CDP), with data, or a dedicated charging port (DCP), without data. Dedicated charging ports can be found on USB power adapters to run attached devices and battery packs. Charging ports on a host with both kinds will be labeled. [59]
Standard USB hub ports can provide from the typical 500 mA/2.5 W of current, only 100 mA from non-hub ports. USB 3.0 and USB On-The-Go supply 1.8 A/9.0 W (for dedicated battery charging, 1.5 A/7.5 W full bandwidth or 900 mA/4.5 W high bandwidth), while FireWire can in theory supply up to 60 watts of power, although 10 to 20 watts is more typical.
The threat surface of a USB however is bi-directional and a malicious peripheral device could attack the host. An infected edge device cannot easily be mitigated by WebUSB API's. In many device configurations trusted USB ports are used to deliver firmware upgrades and a malicious edge device could grant attackers persistence in a system. [11] [4]
For example, a USB 2 PCIe host controller card that presents 4 USB "Standard A" connectors typically presents one 4-port EHCI and two 2-port OHCI controllers to system software. When a high-speed USB device is attached to any of the 4 connectors, the device is managed through one of the 4 root hub ports of the EHCI controller.
USB 3.0 SuperSpeed – host controller (xHCI) hardware support, no software overhead for out-of-order commands; USB 2.0 High-speed – enables command queuing in USB 2.0 drives; Streams were added to the USB 3.0 SuperSpeed protocol for supporting UAS out-of-order completions USB 3.0 host controller (xHCI) provides hardware support for streams
In addition to an empty PCIe slot on the motherboard, many "PCI Express to USB 3.0" expansion cards must be connected to a power supply such as a Molex adapter or external power supply, in order to power many USB 3.0 devices such as mobile phones, or external hard drives that have no power source other than USB; as of 2011, this is often used ...
USB-C plug USB-C (SuperSpeed USB 5Gbps) receptacle on a laptop. USB-C, or USB Type-C, is a 24-pin, reversible connector (not a protocol) that supersedes previous USB connectors and can carry audio, video, and other data, to connect to monitors, external drives, hubs/docking stations, mobile phones, and many more peripheral devices.