A type of multiplexor
that combines multiple channels
onto a single transmission medium in such a way that all the individual channels can be simultaneously active. For example, ISPs
use concentrators to combine their dial-up
modem connections onto faster T-1 lines
that connect to the Internet
Concentrators are also used in local-area networks (LANs) to combine transmissions from a cluster of nodes. In this case, the concentrator is often called a hub or MAU.