Smart Technologies SMART Board 800 Series User Manual page 20

A P P E N D I X A
USB 2.0 specification primer
Term Definition
Downstream The direction of data flow from the host or away from the host. A
downstream port is the port on a hub electrically farthest from the host that
generates downstream data traffic from the hub. Downstream interfaces
receive upstream data traffic.
Full-speed USB operation at 12 Mbps
Function A USB device that provides a capability to the host, such as a keyboard,
interactive whiteboard or speakers.
High-speed USB operation at 480 Mbps
Host The host computer system where the USB host controller is installed. This
includes the host hardware platform (CPU, bus, etc.) and the operating
system in use.
Host controller The host's USB interface hardware and software
Hub A USB device that provides additional connections to the bus
Low-speed USB operation at 1.5 Mbps
Passive An extension cable that has no active electronic components. For more
(extension cable) information, see Prohibited cable assemblies on page 20.
Physical device A device that has a physical implementation; for example, speakers,
microphones, and CD players.
Port A USB hub's downstream connection point where a USB device is
attached
Root hub A USB hub directly attached to the host controller
Upstream The direction of data flow toward the host. An upstream connector on a
device is electrically closest to the host that generates upstream data traffic
from the hub. Upstream interfaces receive downstream data traffic.
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