Universal Serial Bus (USB) & FireWire 

USB

Universal Serial Bus (USB) connects devices to a host computer. USB was designed to allow many peripherals to be connected using a single standardized interface socket and to improve plug and play capabilities by allowing hot swap functionality that does not require rebooting the host system or turning off the device. Other convenient features include providing power to low-consumption devices, eliminating the need for an external power supply; and allowing many devices to be used without requiring manufacturer-specific device drivers to be installed.

USB is replaced many older technologies such as serial and parallel ports that were used by devices such as printers and scanners. USB can connect peripherals such as mice, keyboards, digital cameras, printers, personal media players (iPods), flash drives/memory sticks and finally external disk drives. For many of those devices, USB has become the standard connection method. USB was originally designed for computer systems but it has become commonplace on other devices such as mobile phones, game consoles and set top boxes like Sky TV for example.

Specifications

USB 1.0 was the first specification and was introduced in 1994. It was intended to replace the multitude of connectors at the back of PCs, as well as to simplify software configuration of communication devices. The original USB 1.0 specification had a data transfer rate of 12Mb/s.

USB 2.0 specification was released in April 2000 and was standardized by the USB-IF (USB Implementers Forum) at the end of 2001. USB 2.0 was a big leap forwards in technology and offers a higher transfer rate of 480Mb/s.

USB 3.0 specifications were released in November 2008 by the USB 3.0 Promoter Group. It has a transfer rate of up to 10 times faster than the USB 2.0 version and has been dubbed the SuperSpeed USB. We should see USB 3.0 devices by the end of 2009.

All USB devices are backwards compatible with older versions however an additional power source may be required on a USB 1.0 bus.

Firewire (IEEE-1394)

FireWire, also known as IEEE-1394 or i.LINK, is a high-speed serial bus found in PC, PC Peripherals and CE devices like Camcorders. 

Originally created by Apple and standardized in 1995 as the specification IEEE 1394 High Performance Serial Bus, FireWire is very similar to USB. The designers of FireWire had several particular goals in mind when they created the standard: 

• Fast transfer of data 
• Ability to put lots of devices on the bus 
• Ease of use 
• Hot-pluggable ability 
• Provision of power through the cable 
• Plug-and-play performance 
• Low cabling cost 
• Low implementation cost 

FireWire is a method of transferring information between digital devices, especially audio and video equipment. FireWire is a fast technology with the latest version achieves speeds up to 800 Mb/s.

You can connect up to 63 devices to a FireWire bus and it is supported by both Windows and Mac operating systems. As with USB, FireWire is plug-and-play, so if you connect a new FireWire device to your computer, the operating systems auto-detects. Additionally FireWire devices are also hot pluggable, which means they can be connected and disconnected at any time, even with the power on.

FireWire Specifications

FireWire 400 (1394a) was the original FireWire specification and was faster than USB when it came out. FireWire 400 is still in use today and features transfer rates of up to 400Mb/s with maximum distance between devices of 4.5 meters (cable length). With the release of USB 2.0, featuring transfer speeds up to 480 Mbps and up to 5 meters between devices, the gap closed between these competing standards. 

FireWire 800 (1394b) was released in 2002 which put FireWire speeds back ahead of USB 2.0. FireWire 800 is capable of transfer rates up to 800Mb/s with maximum distance between devices of 100 meters (cable length) 

1394b standard is backward-compatible with 1394a. 

 USB vs. FireWire