1394b

IEEE 1394b, commonly marketed as FireWire 800, is a revision of the IEEE 1394 serial bus standard. It expands the original FireWire family by increasing the maximum data transfer rate from 400 Mbit/s to 800 Mbit/s and by introducing new physical layer options. The specification retains the same isochronous and asynchronous transfer modes used in earlier FireWire versions, enabling real-time multimedia data transfer while offering higher bandwidth for demanding applications such as high-definition video and external storage.

Physical layer and cabling: 1394b adds support for alternate physical layers, including copper and fiber-optic links. This allows longer cable runs and flexible topologies via hubs and bridges. The 800 Mbit/s rate is the marketed speed for FireWire 800 devices, with actual throughput affected by protocol overhead.

Compatibility and impact: 1394b is designed to be backward compatible with devices using 1394a, though performance is constrained by the slowest device on the bus and bridging hardware may be required. It found use in professional video hardware and external storage enclosures during its peak years, particularly in environments requiring higher sustained data rates than FireWire 400 could provide.

Decline and legacy: As USB 2.0 and later USB 3.x and Thunderbolt gained prominence, the adoption of FireWire, including 1394b, declined in consumer markets. Nevertheless, some professional workflows and legacy equipment continued to rely on FireWire 800 for its predictable streaming capabilities.