FireWire 400 is a high-speed data transfer technology developed by Apple in the 1990s. It allows devices to connect and communicate with each other, supporting data rates of up to 400 megabits per second. This makes it suitable for tasks like transferring video and audio files between devices, such as cameras and computers. The standard uses a 6-pin or 4-pin connector, with the 6-pin version providing power to connected devices. FireWire 400 was widely used in professional audio and video equipment but has since been largely replaced by newer technologies like USB 3.0 and Thunderbolt.