In telecommunication, the term concentrator has the following meanings:

• In data transmission, a functional unit that permits a common path to handle more data sources than there are channels currently available within the path. A concentrator usually provides communication capability between many low-speed, usually asynchronous channels and one or more high-speed, usually synchronous channels. Usually different speeds, codes, and protocols can be accommodated on the low-speed side. The low-speed channels usually operate in contention and require buffering.
• A device that connects a number of links with only one destination, the main function of this device is to make a kind of load balancing between two or more servers connected together, data distribution is done according to the server processing rate.
• A patch panel or other component in the cable plant where cable runs converge.
• ISP used concentrators to enable modem dialing; this kind of concentrator is sometimes called a modem concentrator or a remote access concentrator. The term "access concentrator" is also used to describe similar provider edge equipment used in computer networks that doesn't rely on modems anymore, e.g. FTTH.