1. \Con"cen*tra`tor\, n. (Mining)
   An apparatus for the separation of dry comminuted ore, by
   exposing it to intermittent puffs of air. --Knight.
   

2. \Con"cen*tra`tor\, n. (Firearms)
   A frame or ring of wire or hard paper fitting into the
   cartridge case used in some shotguns, and holding the shot
   together when discharged, to secure close shooting; also, a
   device for slightly narrowing the bore at the muzzle for the
   same purpose.
   

A device that combines the data streams from many simultaneously active inputs into one shared channel in such a way that the streams can be separated after transmission. The concentrator's output bandwidth must be at least as great as the total bandwidth of all simultaneously active inputs. A concentrator is one kind of multiplexing device.

For example, a concentrator may be used to connect 24 2400 bps TTYs to a host via a 57600 bps channel.