Serial Device Server, Serial Port RS-232/485/422 to Fiber Converter, Fiber Optic MODEM

Product Highlights

The SH-M277 is a multi-functional fiber optic MODEM supporting asynchronous RS-232, RS-485, and RS-422 interfaces, ideal for connecting RTUs to hosts or SCADA controllers. It allows mixed use of two such interfaces, supports 2-wire half-duplex RS-485 and 4-wire full-duplex RS-422, with RS-485 enabling data transmission control. It facilitates full/half-duplex communication over fiber (up to 4km multi-mode, 20km single-mode), with max rates 115.2Kbps (RS-232) and 460Kbps (RS-485/422). It replaces interface converters/isolators, supports mixed electrical standards, and offers excellent EMI/RFT performance.

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Product Detail

Description

SH-M277 is a multi-functional fiber optic MODEM supporting asynchronous RS-232, RS-485 and RS-422 communication interfaces. It is the optimal choice for connecting Remote Terminal Units (RTU) to host computers (HOST) or Distributed Data Acquisition System (SCADA) controllers.

It supports multiple asynchronous communication protocols including RS-232, RS-485 and RS-422, and allows simultaneous mixed use of two RS-232, RS-485 or RS-422 interfaces. It supports 2-wire (half-duplex) RS-485 and 4-wire (full-duplex) RS-422 working modes.

The RS-485 mode of SH-M277 supports data (TXD or SD) transmission control, thereby enhancing adaptability to various software and simplifying control methods. The fiber optic MODEM supports multiple fiber optic connection modes between asynchronous serial ports, enabling full-duplex or half-duplex communication between devices with two asynchronous serial ports via optical fiber. The maximum communication distance can reach 4km for multi-mode fiber and 20km for single-mode fiber. The maximum transmission rate is 115.2Kbps for RS-232 signals and 460Kbps for RS-485/RS-422 signals.

Interfaces with different electrical standards can be mixed. RS-232 devices can be connected to RS-485/RS-422 devices, making it a replacement for RS-232 to RS-485/422 interface converters or photoelectric isolators, while providing excellent EMI/RFT characteristics.

Buying Guide

Model	Specifications
SH-M277S-20	Serial port RS-232/485/422 to fiber converter, single-mode dual-fiber 1310nm 20km ST DC 9-48V
SH-M277M-4	Serial port RS-232/485/422 to fiber converter, multi-mode dual-fiber 1310nm 4km ST DC 9-48V
SH-MS277A-20	Serial port RS-232/485/422 to fiber converter, single-mode single-fiber T1310/R1550nm 20km ST DC 9-48V
SH-MS277B-20	Serial port RS-232/485/422 to fiber converter, single-mode single-fiber T1550/R1310nm 20km ST DC 9-48V
SH-M277A-4	Serial port RS-232/485/422 to fiber converter, multi-mode single-fiber T1310/R1550nm 4km ST DC 9-48V
SH-M277B-4	Serial port RS-232/485/422 to fiber converter, multi-mode single-fiber T1550/R1310nm 4km ST DC 9-48V

Parameter

Item	Specification
RS-232 interface	Standard RS-232 three-wire interface with ±15KV (ESD) protection, supporting a maximum speed of 115.2Kbps
RS-485/422 interface	Adopts port adaptive technology to realize adaptive adjustment from port to speed without switch setting, with ±15KV (ESD) protection and 600W surge protection per line, supporting up to 32-point polling environment
Asynchronous Transmission	Point-to-point application, speed up to 460Kbps
Wavelength	1310nm (multimode); 1310nm, 1550nm (single-mode)
Transmission Distance	4km for multimode; 20km for single-mode
Indicators	TXD: Fiber interface data transmission indicator RXD: Fiber interface data reception indicator PWR: Power indicator
Operating Temperature	-40℃ to +85℃, relative humidity 5% to 95%
Electrical Interfaces	RS-232: Using terminal block connector RS-485/422: Using terminal block connector Fiber interface: ST type (SC/FC optional)
Power Supply	Input voltage DC 9-48V, current 200mA