Feeds

Inside USB 3.0

What makes SuperSpeed tick

Reducing security risks from open source software

Adaptive equalisation also helps the host cope with controlling one set of USB 3.0 ports nearby at the front of a PC and with those mounted on the backplane, much further away and so connected over a greater length of wire.

USB 3.0 SuperSpeed

The wire: what links one USB 3.0 device to another

SuperSpeed USB will be the first interconnect to use this kind of technology. Even HDMI, which can transfer data at up to 3.4Gb/s, doesn't rely on it. HDMI is the closest high-speed data transfer system to USB 3.0 in that connections likewise run over cables whose quality and length the standard has no control over.

Compare that to buses like Sata and PCI Express 2.0 - on which USB 3.0 is largely based - where the lane lengths, while not set in stone, can be assumed to be very short with well-defined signal attenuation characteristics.

The USB 1.1 and USB 2.0 specifications defined maximum cable lengths of 3m and 5m, respectively. USB 3.0 knocks the maximum back down to 3m.

USB 3.0 - Cable Profile

Inside a USB 3.0 cable

That said, since USB 3.0 is backward compatible with 2.0, connecting your current thin-wired mouse to a USB 3.0 port isn't going to be a problem. Indeed, as you'll see from the picture above, the USB 3.0 cable contains a separate USB 1.1/2.0 Unshielded Twisted Pair (UTP) cord - more on this crucial component later.

And the mouse's USB connector will still work too, mechanically and electrically. The basic USB 3.0 'Standard A' connector looks like today's big USB plugs - it's just longer, to accommodate five extra, rear-mounted pins which will mate up correctly in a standard USB 3.0 socket. Insert a USB 2.0 port instead, and the device will still work, just at the 'old' 480Mb/s speed.

Bus Architecture

SuperSpeed's Standard A port pair

Those extra pins provide a second ground connection, plus two pairs of lines, one for sending data the other for receiving it. Having separate wires for transmission and for reception means USB 3.0 links can be used to read and write data simultaneously - 'dual simplex' signalling, in the jargon, compared to USB 2.0's 'half duplex' operation. Previous versions of USB had two data wires, but they could only operate as uplinks or downlinks at any given time, not both.

Securing Web Applications Made Simple and Scalable

More from The Register

next story
Child diagnosed as allergic to iPad
Apple's fondleslab is the tablet dermatitis sufferers won't want to take
Microsoft takes on Chromebook with low-cost Windows laptops
Redmond's chief salesman: We're taking 'hard' decisions
For Lenovo US, 8-inch Windows tablets are DEAD – long live 8-inch Windows tablets
Reports it's killing off smaller slabs are greatly exaggerated
Seventh-gen SPARC silicon will accelerate Oracle databases
Uncle Larry's mutually-optimised stack to become clearer in August
EU dons gloves, pokes Google's deals with Android mobe makers
El Reg cops a squint at investigatory letters
Big Blue Apple: IBM to sell iPads, iPhones to enterprises
iOS/2 gear loaded with apps for big biz ... uh oh BlackBerry
prev story

Whitepapers

Reducing security risks from open source software
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Application security programs and practises
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Consolidation: the foundation for IT and business transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.