A January 2013 press release from the USB group revealed plans to update USB 3.0 to 10 Gbit/s.[26] The group ended up creating a new USB version, USB 3.1, which was released on 31 July 2013,[27] introducing a faster transfer mode called "SuperSpeed USB 10 Gbit/s", putting it on par with a single first-generation Thunderbolt channel. The new mode's logo features a "Superspeed+" caption (stylized as SUPERSPEED+). The USB 3.1 standard increases the data signaling rate to 10 Gbit/s in the USB 3.1 Gen2 mode, double that of USB 3.0 (referred to as USB 3.1 Gen1) and reduces line encoding overhead to just 3% by changing the encoding scheme to 128b/132b.[28] The first USB 3.1 implementation demonstrated transfer speeds of 7.2 Gbit/s.[29]
The USB 3.1 standard is backward compatible with USB 3.0 and USB 2.0.
The USB Type-C Specification 1.0 defines a new small reversible-plug connector for USB 3.1 devices. The type-C plug will be used at both host and device side, replacing multiple type-B and type-A connectors and cables with a future-proof[30] standard similar to Apple Lightning and Thunderbolt.[31][32] The 24-pin double-sided connector provides four power/ground pairs, two differential pairs for USB 2.0 data bus (though only one pair is implemented in a type-C cable), four pairs for high-speed data bus, two "sideband use" pins, and two configuration pins for cable orientation detection, dedicated biphase mark code (BMC) configuration data channel, and VCONN +5 V power for active cables.[33][34] Type-A and type-B adaptors/cables will be required for legacy devices in order to plug into type-C hosts, however adaptors/cables with a type-C receptacle are not allowed.
Full-featured USB 3.1 type-C cables are active electronically marked cables and contain a chip with an ID function based on the configuration data channel and vendor-defined messages (VDMs) from the USB Power Delivery 2.0 specification. USB 3.1 type-C devices also support power currents of 1.5 A and 3.0 A over the 5 V power bus in addition to baseline 900 mA; devices can either negotiate increased USB current through the configuration line, or they can optionally support the full Power Delivery specification using both BMC-coded configuration line and legacy BFSK-coded VBUS line.
Alternate Mode dedicates some of the physical wires in the type-C cable for direct device-to-host transmission of alternate data protocols. The four high-speed lanes, two sideband pins, and - for dock, detachable device and permanent cable applications only - two USB 2.0 pins and one configuration pin can be used for Alternate Mode transmission. The modes are configured using VDMs through the configuration channel. As of December 2014, Alt Mode implementations include DisplayPort 1.3 [35] and MHL 3.0;[34][36] other serial protocols like PCI Express and Base-T Ethernet are possible.
A January 2013 press release from the USB group revealed plans to update USB 3.0 to 10 Gbit/s.[26] The group ended up creating a new USB version, USB 3.1, which was released on 31 July 2013,[27] introducing a faster transfer mode called "SuperSpeed USB 10 Gbit/s", putting it on par with a single first-generation Thunderbolt channel. The new mode's logo features a "Superspeed+" caption (stylized as SUPERSPEED+). The USB 3.1 standard increases the data signaling rate to 10 Gbit/s in the USB 3.1 Gen2 mode, double that of USB 3.0 (referred to as USB 3.1 Gen1) and reduces line encoding overhead to just 3% by changing the encoding scheme to 128b/132b.[28] The first USB 3.1 implementation demonstrated transfer speeds of 7.2 Gbit/s.[29]
The USB 3.1 standard is backward compatible with USB 3.0 and USB 2.0.
The USB Type-C Specification 1.0 defines a new small reversible-plug connector for USB 3.1 devices. The type-C plug will be used at both host and device side, replacing multiple type-B and type-A connectors and cables with a future-proof[30] standard similar to Apple Lightning and Thunderbolt.[31][32] The 24-pin double-sided connector provides four power/ground pairs, two differential pairs for USB 2.0 data bus (though only one pair is implemented in a type-C cable), four pairs for high-speed data bus, two "sideband use" pins, and two configuration pins for cable orientation detection, dedicated biphase mark code (BMC) configuration data channel, and VCONN +5 V power for active cables.[33][34] Type-A and type-B adaptors/cables will be required for legacy devices in order to plug into type-C hosts, however adaptors/cables with a type-C receptacle are not allowed.
Full-featured USB 3.1 type-C cables are active electronically marked cables and contain a chip with an ID function based on the configuration data channel and vendor-defined messages (VDMs) from the USB Power Delivery 2.0 specification. USB 3.1 type-C devices also support power currents of 1.5 A and 3.0 A over the 5 V power bus in addition to baseline 900 mA; devices can either negotiate increased USB current through the configuration line, or they can optionally support the full Power Delivery specification using both BMC-coded configuration line and legacy BFSK-coded VBUS line.
Alternate Mode dedicates some of the physical wires in the type-C cable for direct device-to-host transmission of alternate data protocols. The four high-speed lanes, two sideband pins, and - for dock, detachable device and permanent cable applications only - two USB 2.0 pins and one configuration pin can be used for Alternate Mode transmission. The modes are configured using VDMs through the configuration channel. As of December 2014, Alt Mode implementations include DisplayPort 1.3 [35] and MHL 3.0;[34][36] other serial protocols like PCI Express and Base-T Ethernet are possible.
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