Firewire Vs. USB

In the realm of personal computing and consumer electronics, there are not one but two high speed serial bus interfaces: USB and Firewire. Both have achieved what they were designed to do by facilitating the connection of external devices to each other and to computers. As a consequence, both have been widely adopted by the consumer market. Though each is a serial interface, there are important differences between them.

USB History

The USB specification has gone through three revisions. USB 1.0 was introduced in 1994 with a speed of 12 Mbits/s. USB 2.0 was standardized at the end of 2001 with a speed of 480 Mbits/s. The USB 3.0 specification was released in November 2008, and should achieve speeds up to 5,000 Mbits/s or 5 Gbits/s. The first USB 3.0 devices appear in 2009 or 2010.

Firewire History

Apple began development of Firewire in the late 1980s. Eventually they presented it to the IEEE, which finalized it in 1995 as IEEE-1394. Top speed was 400 Mbits/s. The standard is often referred to as S400. IEEE 1394b was introduced in 2002, and had a top speed of 800 Mbits/s. It is also referred to as S800. 1600 Mbits/s and 3200 Mbits/s modes were announced in December 2007.

Uses

USB has become the most widely used means of connecting low and medium-speed peripheral devices like keyboards, mice, printers, scanners, external hard drives, digital cameras and flash drives to personal computers. Firewire has become the primary transfer mechanism for almost all high end professional audio and video equipment. It is a popular option on computers set up for audio and video editing. It has also been incorporated into automobiles and military aircraft.

USB Connectors

USB has several connector types, but all of them use four data pins. USB-A, the most common type, is rectangular. There are also USB-B, USB Mini-A, USB Mini-B, Micro-AB, and Micro-B connectors with distinctive square, rectangular and trapezoid shapes. All have a smaller profile than USB-A.

Firewire Connectors

Firewire S400 was introduced with 4-pin and 6-pin connectors. The 6-pin variant was more widely adopted. Firewire S800 uses a squarish 9-pin connector. The S1600 and S3200 versions are expected to use the 9-pin as well.

Performance

Although USB 2.0 has a higher stated speed at 480 Mbit/s, it rarely transfers data at more than 280 Mbits/s. FireWire S400 by contrast sustains much higher throughput. The difference is due in part to USB's greater reliance on a computer CPU to manage interrupts and buffering. Firewire also provides more power and is a more reliable data transfer.