DC04-485 Four Door Controller 1. 4 doors, 4 Card Readers 2. 20, ... to the computer and activity reports are printed. Each controller works independently and keeps its own database. Parameter index ... and never lose data Max distance between reader to the controller: 100 meters, suggest within 80 meters, Max distance ... line can reach up to 3000 meters RS485 Four Door Access Controller, 4 door / 4 readers