IEEE 1394 is a high-speed, serial input/output port for connecting computer peripherals and consumer electronics. IEEE 1394 has two types of ports they are IEEE 1394A and IEEE 1394B. IEEE 1394A is capable of transferring data at speeds of up to 400 megabits per second and IEEE 1394B is capable of transferring data at speeds of 800 megabits per second. It is the fastest external input/output bus available and can support up to 63 devices. It is optimal for bandwidth-hungry devices such as digital video cameras and external storage devices.
IEEE 1394 also has the added advantage of delivering data both asynchronously and isochronously. In asynchronous mode data transfers can be interrupted but in isochronous mode data is transferred without interruption.
While transferring data asynchronously, IEEE 1394 allocates bandwidth to devices as needed. When one device needs to communicate with another, it sends out a signal.
There is a possibility that the devices may get the bus with the desired bandwidth or they might have to wait before getting the requested bandwidth. However, this procedure doesn't work for applications such as streaming video. Here, if another device requests space on the bus, the video data stream will be interrupted which results in degrading the image quality. To overcome this, IEEE 1394 offers isochronous mode, which guarantees that video and similar devices consistently get the bandwidth they require.
