THE USB CONNECTION

by Jack Korten (Australia)

The basic USB trident logo.


This USB sign is on the head of a USB Cable.

Universal Serial Bus (USB) is an industry standard developed in the mid-1990s that defines the connection, communication and power supply between computers and electronic devices. A group of seven companies began the development of USB in 1994: Compaq, DEC, IBM, Intel, Microsoft, NEC and Nortel. The goal was to make it fundamentally easier to connect external devices to PCs by replacing the multitude of connectors at the back of PCs. The first integrated circuits supporting USB were produced by Intel in 1995.

USB has effectively replaced a variety of earlier interfaces such as, serial and parallel ports as well as separate power chargers for portable devices.

Unlike other data cables (e.g. HDMI), each end of a USB cable uses a different kind of connector; an A-type or a B-type.

A Standard-B plug—which has a square shape with bevelled exterior corners— typically plugs into an "upstream receptacle" on a device that uses a removable cable, e.g., a printer. This kind of design was chosen to prevent electrical overloads and damaged equipment, as only the A- type socket provides power.

The Micro-USB connector was announced in January 2007. While many currently available devices and cables still use Mini plugs the newer Micro connectors are presently the most widely used. The thinner micro connectors replace the Mini plugs in new devices including smartphones, personal digital assistants, and cameras.

Some manufacturers of electronic devices might not include a USB standard connector on their product for technical or marketing reasons. Some devices only use the USB connection for battery charging and do not implement any data transfer functions.

USB connections also come in four data transfer speeds: Low Speed, Full Speed, High Speed and SuperSpeed. SuperSpeed is supported only by USB 3.0 interfaces.

The original USB 1.0, which was introduced in January 1996 which had transfer rates of 1.5 Mbit/s "Low Speed" and 12 Mbit/s "Full Speed".

The USB 2.0 specification published in April 2000 achieved 480 Mbit/s, or 40-times faster than the original USB 1.1 specification.

The USB 3.0 specification was released in November 2008. It increased the data transfer rate up to 5 Gbit/s, decreasing power consumption at the same time. The first USB 3.0 equipped devices were presented in January 2010.

The cable displays the basic USB trident logo, followed by SS, for SuperSpeed, whilst the port is coloured blue.

USB 3.1 (SuperSpeed +) will be released in the not- too-distant future, with speeds twice as fast as version 3.0.

USB 3.1 introduces a new cable and connector, which is designed to replace both full-sized USB, as well as micro-USB cables, thereby standardising the port and cable types across devices. USB Type-C cables will also be reversible, allowing you to plug them in without fail regardless of how you’re holding and inserting the cable.

Needless to say, the plugs aren’t compatible with anything you currently own.

The USB Implementers Forum is also working on a wireless networking standard.
Wireless USB is intended as a cable
-replacement technology, and uses ultra-wideband wireless technology for data rates of up to 480 Mbit/s.

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