USB 3.0 is the improvedversion of USB (Universal Serial Bus) that provides better speed and moreefficient power management than USB 2.0. USB 3.0 is backward compatible withUSB 2.0 devices; however, data transfer speeds are limited to USB 2.0 levelswhen these devices inter-operate. In 2014, a new standard, USB 3.1, wasreleased and is expected to be in widespread use by 2015.
What is USB 3.0 and USB2.0?
Developed in the 1990s, the Universal Serial Bus(USB) standard was developed to define communication protocols, includingcables and connectors, between computers and electronic devices such asprinters and scanners. As the number of devices multiplied in quantity andtypes, the USB port was adopted as the basic connection portal.
Devices like smartphones, PDAs, tablets,smartphones and video game consoles can connect to computers with USB portsallowing recharging and communication thereby replacing the requirement ofadapters and power chargers.
USB3.0 was released in November 2008, almosteight years after the release of USB 2.0. Over five years later, in 2014, USB3.1 was released with widespread use expected in 2015.
What is USB 3.1?
The newest standard is for USBs is USB 3.1. Itoffers three major improvements over 3.0: an "always right" C-typeconnector that plugs in without regard to orientation, higher data transferspeeds of up to 10 gigabytes per second, and the capacity to power any type ofdevice.
The C-Type connector is small enough for modern,slim devices, such as Macbook Air-type notebooks, tablets, andsmartphones. but still robust enough for 10,000 cycles of use. Data transferspeeds are more in sync with current app and user needs, especially for videoand image files. And the option to connect to and power any type of device,with 100 watts of charging power that can be divided between two devices,greatly reduces "charger and cable clutter," simplifying connectivitybetween personal devices. However, backwards compatibility will be limited.
USB 3.0 Highlights and Benefits over USB 2.0
· Transferrates: USB 2.0 offers transfer rates of 480 Mbps, and USB 3.0 offerstransfer rates of 4.8 Gbps 10 times faster.
· Additionof another physical bus: The amount of wires was doubled, from 4 to 8.Additional wires required more space in both the cables and connectors, so newtypes of connectors were designed.
· Powerconsumption: USB 2.0 provides up to 500 mA whereas USB 3.0 provides up to900 mA. The USB 3 devices provide more power when needed and conserve powerwhen the device is connected but idling.
· Morebandwidth: Instead of one-way communication, USB 3.0 uses twounidirectional data paths, one to receive data and the other to transmit whileUSB 2.0 can only handle only one direction of data at any time.
· Improvedbus utilization: A new feature was added (using packets NRDY and ERDY) tolet a device asynchronously notify the host of its readiness.
When data is being transferred through USB 3.0devices, cables, and connectors, the transaction is initiated by the hostmaking a request followed by a response from the device. The device eitheraccepts the request or rejects it. If accepted, the device sends data oraccepts data from the host. If there is lack of buffer space or data, itresponds with a Not Ready (NRDY) signal to tell the host that it is not able toprocess the request. When the device is ready then, it will send an EndpointReady (ERDY) to the host which will then reschedule the transaction.
USB 3.0 Connectors are different from USB 2.0Connectors and the 3.0 connectors are usually colored blue on the inside inorder to distinguish them from the 2.0 connectors.
USB 3.0 is compatible with USB 2.0. However, theUSB 3.0 product will perform at the same level as a USB 2.0 product, so speedand power benefits will not be fully realized.
USB 3.0 receptacles are electrically compatiblewith USB Standard 2.0 device plugs if they physically match. USB 3.0 type-Aplugs and receptacles are completely backward compatible, and USB 3.0 type-Breceptacles will accept USB 2.0 and earlier plugs. However, USB 3.0 type-Bplugs will not fit into USB 2.0 and earlier receptacles.
This means that USB 3.0 cables cannot be usedwith USB 2.0 and USB 1.1 peripherals, although USB 2.0 cables can be used withUSB 3.0 devices, if at USB 2.0 speeds.
For a similar product, the USB 3.0 version isgenerally more expensive than its USB 2.0 version.
Which version is your USB port?
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