Universal Serial Bus (USB) remains the most widely used cabled IO bus and is found in systems ranging from embedded controllers to workstations and servers. While USB 3.2 is the latest specification version for generic USB 2.0 and Enhanced SuperSpeed (ESS), the addition of USB4 introduces an entirely new capability--interleaved USB 3.2, PCI Express (PCIe), and DisplayPort (DP) packets on the multi-protocol USB4 link. One of the most important use cases for multiplexed IO protocols over a single bus applies to laptops, notebooks, tablets, and other small form factors where space is limited for both internal peripherals and external IO connectors. In this scenario, a USB4 dock may be connected to the host; downstream of the dock may be native protocol PCIe, USB 3.2, and DisplayPort peripherals: SSD, GPU, LAN adapter, multiple displays, etc. If a dock isn’t needed, a USB4 port can be dedicated to a high bandwidth peripheral or charging power.

USB4 employs an enhanced version of Intel’s Thunderbolt 3 packet tunneling scheme to support multiple protocols on a physical interface based on USB-C defined connectors, cables, and power delivery (USB PD). The USB-C connection used by USB4 also supports the backward compatibility required if native USB 3.x, USB 2.0, or DisplayPort alternate mode devices are attached to USB4-capable USB-C ports.

Watch Introductory Video: