Cables and Connectors

What Is an S400 Port

An S400 port, commonly known as a FireWire 400 port, is a type of connection interface for high-speed data transfer. It was developed by Apple and was standardized as IEEE 1394, an interface standard for a serial bus for high-speed communications and isochronous real-time data transfer. Here are some key aspects of the S400 (FireWire 400) port:

Key Features of FireWire 400 (S400)

  1. Speed: The “400” in FireWire 400 indicates its maximum data transfer speed of 400 Mbps (megabits per second).
  2. Connectivity: It was commonly used to connect digital video cameras, external hard drives, and other devices to computers.
  3. Daisy Chaining: FireWire 400 allows for daisy-chaining up to 63 devices to a single port, without significant performance degradation.
  4. Plug-and-Play and Hot-Swappable: Devices can be connected and disconnected without rebooting the computer or turning off the device.
  5. Cable Length: The standard supports cable lengths up to 4.5 meters, but longer cables can be used with the help of repeaters.

Connector Types

  • FireWire 400 came in two types of connectors:
    • 4-Pin Connector: Typically used for smaller devices like digital cameras, with no power supply through the cable.
    • 6-Pin Connector: Larger, used for desktop applications, and can supply power to the connected device.


Comparison with USB

  • While similar in function to USB, FireWire 400 was often preferred for its consistent data transfer rates, which was essential for video and audio applications.
  • USB 2.0, a contemporary of FireWire 400, had a higher theoretical maximum speed (480 Mbps) but did not always maintain consistent transfer rates, making FireWire 400 a better choice for certain applications.

Decline and Legacy

  • The popularity of FireWire 400 declined with the advent of USB 3.0 and Thunderbolt technologies, which offered higher speeds and more versatility.
  • FireWire 400 was succeeded by FireWire 800 (IEEE 1394b), which doubled the maximum data transfer speed to 800 Mbps.

Current Relevance

  • As of now, FireWire 400 is largely obsolete in most consumer applications, but it might still be found in some professional audio and video environments.
  • Modern computers rarely include FireWire ports, but FireWire devices can still be used with the help of adapters (e.g., FireWire to USB or FireWire to Thunderbolt).

The S400 port played a significant role in the development of digital multimedia and professional content creation, providing a reliable high-speed connection that was critical for many applications in the early 2000s.

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