The fiber optic converter is a multifunctional fiber optic MODEM that supports asynchronous RS-232, RS-485, and RS-422 communication interfaces. It is used to connect the remote terminal unit (RTU) to the host (HOST) or distributed data acquisition system (SCADA) controller. HESF-T series supports a variety of asynchronous communication protocols such as RS-232, RS-485 and RS-422. Two RS-232, RS-485 or RS-422 interfaces can be mixed at the same time. This series supports 2-wire (half-duplex) RS-485 and 4-wire (full-duplex) RS-422 working mode. The RS-485 mode of the fiber optic converter supports data (TXD or SD) transmission control, which improves the ability to adapt to various software and simplifies the control method. The fiber optic MODEM supports multiple fiber optic connection methods between asynchronous serial ports. It supports two asynchronous serial port devices for full-duplex or half-duplex communication through optical fiber. The communication distance is up to 4 kilometers for multi-mode and 20 kilometers for single-mode. The transmission rate of RS-232 signal is up to 115.2 Kbps. The signal transmission rate of RS-485/RS-422 can reach up to 460 Kbps. Interfaces of different electrical standards can be mixed. RS-232 equipment can be used to connect RS-485/422 equipment, which can replace RS-232 to RS-485/422 interface converter or optical isolator, and provides excellent EMI/RFT characteristics.

This series supports the transmission of two data signals: sending data and receiving data, and also provides an RS-485/422 data transmission automatic enable control circuit with zero-delay conversion time.