Definition: concentrator

A device that combines several communications channels into one. It is often used to tie multiple terminals together into one line. It differs from a multiplexor, which also combines several lines into one, because the total bandwidth of a concentrator's inputs is not equal to its outputs. A concentrator may temporarily store data to allow for this discrepancy, whereas a multiplexor does not.

An Ethernet hub, which is a multiport repeater, is sometimes called a "concentrator."