USB 1.1, sometimes referred to as Full Speed USB, is a Universal Serial Bus (USB) standard that was released in August 1998. The standard has been almost completely replaced by newer standards such as USB 2.0, USB 3.0 and USB4.

There are actually two different “speeds” that a USB 1.1 device can run at: Low Bandwidth at 1.5 Mbps or Full Bandwidth at 12 Mbps. This is significantly slower than the maximum transfer speeds supported by other standards, most notably the 80 Gbps limit of USB4 2.0, but also older standards such as USB 3.0 (5.120 Mbps) and USB 2.0 (480 Mbps).

See our USB Physical Compatibility Chart for a one-page reference that explains what goes with what.

Depending on the choices made by the manufacturer, a particular USB 3.0 device may or may not function properly on a computer or other host designed for USB 1.1, even though the connectors and plugs are physically connected. In other words, USB 3.0 devices may or may not be backwards compatible with USB 1.1.