The Vanderbilt ACTPRO-100 is a single-door access controller without on-board IP, communicating over RS-485 as an expansion node under ACTpro1520e and ACTpro1500e master controllers. It manages reader input and door output for one entrance while sharing the master controller's network uplink. Typical applications include small to medium access-control installations where door-count expansion is added to an existing ACTpro system.