USB 3.0 is coming

Register Hardware has just published Inside USB 3.0 article on new coming USB 3.0 technology. USB 3.0 is sometimes called SuperSpeed USB because of its 5Gb/s peak data-transfer rate. NEC announced first host controller chip for USB 3.0 last week.

Achieving that 5Gb/s data rate has required some hardware changes because simply can’t do SuperSpeed over USB 2.0 cabling. Long time it was thought that fiber optics were needed to get 5Gb/s data rate but now it seems that copper is the way to go because it is cheaper.

The new USB cables will be thicker than those we’re used to and they have more shielded twisted pairs in them to carry the data. The connectors need to change to handle the new wires. The basic USB 3.0 ‘Standard A’ connector looks like today’s big USB plugs but is slightly longer to to accommodate five extra contact pins. 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.

USB 3.0 is not simply a higher-clocked USB 2.0. The new USB 3.0 bus uses different protocol than USB 2.0. USB 3.0 links can be used to read and write data simultaneously – ‘dual simplex’ signalling, compared to USB 2.0′s ‘half duplex’ operation. USB 3.0 evices explicitly route packets from the source to the targets (USB 2.0 simply broadcasts all packets to all connected devices). USB 3.0 retains USB 2.0′s data transfer types and pipe model.

SuperSpeed USB has a dual-bus architecture to allow hosts and hubs to run USB 3.0 right alongside USB 2.0, while plug-in peripherals are limited to use only USB 3.0 or USB 2.0 signaling.

If things go smoothly maybe we could see first USB 3.0-capable PCs by the end of the year and peripherals that can use the 5Gb/s sometimes next year. Then it probably takes some time (maybe years) before everything on USB 3.0 runs smoothly…