... enhance type(isolation voltage 3,500VRM) Features:1) RS-232 to RS-485 interface converter2) Photoelectric Isolation Interface Converter3) Point ... to point, point to multi-point communication4) Supports RS-232 to RS-422/485 conversion, conversion modes can be selected automatically5 ... Closed circuit monitoringe) Security protection systemf) Intelligent card, check on work attendance gate safety system