Apple Computer created the I/O protocol known as FireWire. The formal term defined by the IEEE is also known as IEEE 1394. Sony i.Link and Yamaha mLAN are two additional labels for IEEE 1394, but Apple's FireWire is the most popular.

The FireWire link comes in two main iterations: FireWire 400 (IEEE 1394a) and FireWire 800. (IEEE 1394b). Data transmission speeds of up to 400 Gbps are supported by FireWire 400, which utilizes a 6-pin connection. The 9-pin connection used by FireWire 800 allows for data transfers of up to 800 Gbps. Using an adaptor, FireWire 800 devices can communicate with Macintosh PCs' 2003 introduction of the FireWire 800 port. Both ports allow daisy chaining and can charge linked devices with up to 30 volts.

Given that FireWire is regarded as a high-speed link, it can be used to join auxiliary devices that need quick data transmission rates. External hard disks, video cams, and audio ports are a few examples. FireWire can be used to start a Macintosh computer in target disk mode, allowing the hard drive to appear as an auxiliary device on another machine. A FireWire cable-based networking between two machines is also supported by Mac OS X.

Despite the fact that FireWire has never been as common as USB, it is still a preferred option for recording and video pros. Compared to USB 2.0, which has a maximum speed of 480 Mbps, FireWire can handle rates of up to 800 Mbps. For real-time audio and video capture, even FireWire 400 offers better continuous read and write rates than USB 2.0. FireWire 1600 and 3200 were intended to enable even higher data transmission rates than IEEE 1394 in the future. The Thunderbolt interface, which can transmit data at up to 10,000 Mbps (10 Gbps) and is previously interoperable with numerous interfaces, has supplanted the FireWire interface.