asynchronous communications server (ACS)

An Asynchronous Communications Server (ACS) is a dedicated personal computer( PC) or expansion card that allows other network nodes to access serial ports or modems.

Through an ACS server, users can dial into a long-distance telephone network from local networks. In addition, they can use modems, fax cards, serial ports, or other asynchronously areiting network components across networks.

Asynchronous Communications Servers are also called dial-in/dial-out servers or modem servers.