The SER-485 PRO-SI is an adapter to convert bidirectional signals from RS232 to RS422 and RS485 in industrial environments. In RS485 mode the data direction is managed by the bitrate adaptive function of ART (Automatic Receive Transmit control). ART analyzes the data in real-time, and adapts to the setup of the RS232 port. The SER-485 PRO-SI is an optical isolated variant of the SER-485 PRO. Further the device is Surge Protected up to 4kV. All options and parameters of SER-485 PRO-SI operation are configured by software, controlled via an easy-to-use menu structure. This menu is accessed via standard terminal programs. The SER-485 PRO-SI is a NO Jumper type of device. With SER-485 PRO-SI often used operation modes are selected by simple DIP switches. The full versatility is controlled by the built-in software configuration menu. The behaviour of RS422 and various options of RS485 are selected by an easy-to-use menu structure. The internal termination and BIAS (polarization) resistors allow to prepare the RS485 signals for connection to customers networks. These internal resistors are activated by relays, controlled by the configuration menu. There is no need to open the case for configuration.