What is Firewire?
FireWire is a standardized serial communications bus similar to USB that allows digital devices to talk to one another at high speed. FireWire operates at a maximum speed of 400 Megabits per second and can handle up to 63 connected devices such as hard drives, monitors, printers, computers and cameras. A FireWire system has no need for a host controller; each device on the system can operate on its own but must follow strict rules about when it is allowed to talk.
Because FireWire is standardized, all FireWire compliant devices should easily plug and play. FireWire has also been designed to allow hot plug and unplug. Since each type of FireWire compliant device is assigned a worldwide identification number, there is little possibility of identification conflicts within the system.
FireWire was initially developed at Apple Computer and Apple still retains the FireWire trademark. The Institute of Electrical and Electronics Engineers formalized the rules for communication on a FireWire bus in a document called the IEEE 1394-1995 specification and you will often hear FireWire referred to as IEEE 1394. The IEEE 1394 document defines the electronic and software protocols used to transmit data over a FireWire system and also specifies the format of the cabling and connectors used with FireWire compliant devices.
The FireWire bus system is much different from the data interface that we use now. Currently, one camera interfaces with one frame grabber and communication between the two is optimized for this one-to-one relationship. With a FireWire bus system, many devices can share the communication line. To avoid conflicts between the devices, strict rules are needed to determine which device can talk and when it can talk. The IEEE 1394 specification provides the rules to ensure that communication between the devices on the FireWire bus takes place in an orderly fashion.