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USB switch

A device that allows one or more USB peripherals to connect to multiple computers, one computer at a time. Such a device is often used to share a scanner, printer or external hard drive with two or more computers. The computer is selected manually by pressing buttons on the device or via software.

In order to allow more peripherals to be connected than there are ports on the switch, a USB hub can be connected to one of the switch ports. See USB hub.



USB hub

A device that increases the number of USB ports on a PC. However, since the hub plugs into one of the USB ports on the computer, the total number of additional ports is minus one. For example, a four-port hub adds three new ports. USB hubs are typically used to extend USB sockets to the top of the desk for conveniently connecting external peripherals.

Self Powered Vs. Bus Powered
Self-powered hubs derive their power from a wall outlet and usually provide up to 500 milliamps at each port. In contrast, bus-powered hubs plug only into the computer's USB bus and obtain all their power from the bus. As a result, they have to split the total 500 milliamps among all the ports and the hub itself, which generally draws 100 milliamps. For example, a four port bus-powered hub would have 100 milliamps of power at each port. When not plugged into an AC outlet, a self-powered hub may sometimes be able to function as a bus-powered hub.

Keyboards and mice typically need less than 100 milliamps, but USB drives and external hard disks need more. See USB switch, PoweredUSB and USB.




USB Hubs
Note the self-powered hub at top right. It adds three Type A ports to the computer. Although it provides four Type A ports for devices, it already takes up one on the computer, netting three additional. Monitors may also contain a USB hub, which can be self powered or bus powered.






Personal Use Only

Before/After Your Search Term
BeforeAfter
USB PCUSB thumb drive
USB phoneUSB-to-SCSI adapter
USB plugsUSB token
USB portUSB toy
USB port replicatorUSB turntable
USB powerline adapterUSB Type A
USB printerUSB Type B
USB RAID driveUSB Type C
USB stickUSB wireless dongle
USB storage deviceUSCD p-System

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