A router (rooter) or, to many, pronounced rowter, is a device that allows several computers to be connected to each other in order to inter-communicate. EG: Share files, share a connection to a WAN or another LAN, etc.
A scanner, well that can mean alot of things. A programme to check what ports you have open or a device to convert a photograph to a digital image.
And to my knowledge you cannot choke your uploads. The speed would be decided by the speed of your connection.
