Remote Access Servers are high-level intelligent devices with multiple asynchronous communication ports that connect to modems and provide remote users with dial-in access to a central-site network. You can configure your RAS to operate via remote control or remote node access. Get more information here.
Remote-control operation enables remote users to send keystroke data and receive screen output from the central site. The actual processing takes place inside the communication server. Remote node access enables the remote user to become a network node and all remote workstations to function as if they were connected locally.