Serial to Fiber Converter RS-232 RS-422 RS-485 to Fiber Optic Modem RS422 RS485 RS232 Serial Media Converter Adapter UT-277SM-ST

Support RS-232, RS-485, RS-422 asynchronous communication protocols
Can mix two RS-232, RS-485 or RS-422 interfaces at the same time.
Supports 2-wire (half-duplex) RS-485 and 4-wire (full-duplex) RS-422 operating modes.
Supports data (TXD or SD) transmission control.
This improves the ability to adapt to various types of software and simplifies the control method.

Supports multiple fiber optic connections between asynchronous serial ports
It supports full-duplex or half-duplex communication between two devices with asynchronous serial ports via optical fiber, with a communication distance of up to 20 km in single mode, and a transmission rate of 115.2Kbps for RS-232 signals and 460Kbps for RS-485/RS-422 signals.

The interfaces of different electrical standards can be mixed
RS-232 devices can be used to connect RS-485/RS-422 devices, which can replace RS-232 to RS-485/422 interface converters or optoisolators, and provide EMI/RFT characteristics.

Support 2 data signal transmission
Transmitting data and receiving data, and also provides automatic enable control circuit for data transmission of RS-485/RS 422.

Zero-delay conversion
All serial ports are connected via terminal blocks, and the fiber optic connection is through two ST connectors.
It is the best choice for connecting remote terminal unit (RTU) to host computer (HOST) or distributed data acquisition system (SCADA) controller.
RXD:

Blinking: means no data is being sent from the fiber port
Out: means no data on the fiber port
Always on: means the serial port is connected backwards or below the bus detection voltage
TXD:

Blinking: means no data is being sent from the fiber port
Out: means no data on the fiber port
Always on: means the fiber is not working or reversed
PWR:

Always on: means the power supply is normal
Off: means the power supply is not normal
UOTEK RS-232 RS-485 RS-422 Fiber Optic Modem - Fast Internet Speed & No Lag Single-mode communication distance up to 20 km Equipped with power adapter Wide range of applications Singlemode Fiber Optic Transceiver - Generally used in pairs