The FD-20i provides input point expansion capacity for all FS, FG+ and FW series controllers. The FD20i has 20 input points, supports BACnet MSTP or Modbus RTU as a selectable function and is equipped with a RS485 port. The inputs include 10 Digital Inputs (DI) and 10 Universal Inputs (UI) supporting resistance based (10K or 20K) or digital dry contact.