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USB to RS-422/485 Adapter with Optical isolation & surge protection

Special Price $99.98

Regular Price: $145.98

Quick Overview

USB to RS-422 / RS-485 Adapter with Optical isolation & surge protection is USB powered and is automatically configured and installed when connected.

Availability: In stock



Manufacturer: SerialGear


The USB-COMi-SI-M USB to RS-422 and RS-485 Adapter with Optical isolation & surge protection is a USB powered serial adapter that is automatically detected and installed once connected to your host computer. There are no IRQ & COM port conflicts, since the port do not require any additional IRQ, DMA, memory as resources on the system. No External Power Needed!

The USB-COMi-SI-M adapter is designed with an external 4-pin dip switch to set RS-422 or RS-485 modes conveniently, without the need to open the metal chassis. Both a 6-pin terminal block and a DB9 male connector are available for optimal flexibility for serial connection. The adapter also provides a unique feature of supplying power output of 5V/150mA through pin-5 of the terminal block to serial device.

Optical isolation and surge protection are available where the serial line of the RS-422/485 port is optically isolated with 2000 volt DC optical isolation. The optical isolation protects your PC from spikes and surges on the RS-422/485 network, by converting the electrical pulse into an optical signal and then changing it back into an electrical pulse. The surges and spikes cannot cross the optical link. The adapter is built-in surge protector to withstand electrostatic discharge and power surges up to 25KV ESD.

The adapter is with DIN rail bracket for industrial environment. Termination and biasing options are available for data transmission lines.


Provides instant connectivity to RS-422, RS-485 communication to:

  • POS
  • Factory automation equipment
  • Multi-drop data collection devices
  • Bar code readers
  • Time clocks, scales
  • Data entry terminals
  • PC to PC long distance communications
  • ATMs and serial communication in harsh environments

The USB-COMi-SI-M USB to Industrial I/O provides an industrial solution requiring single node or multi-drop communications over short and long distance.


Additional Features and Specifications:

  • Adds one RS-422 or RS-485 serial port by connecting to a USB port
  • 2000V DC optical isolation
  • 25KV ESD surge protection
  • No need to open chassis to set operation modes- one external DIP switch for easy RS-422, RS-485 mode settings
  • Installed as standard Windows COM port
  • SECC metal chassis with DIN rail bracket
  • RS-422 data signals: TxD-, TxD+, RxD+, RxD-, GND, RTS-, RTS+, CTS+, CTS-
  • RS-485 4-wire data signals: TxD-, TxD+, RxD+, RxD-
  • RS-485 2-wire data signals: Data-, Data+
  • Automatic transmit and receive control for 2-wire RS-485 half-duplex mode
  • High speed serial port with the baud rate up to 921.6K bps
  • Non-standard baudrates supported
  • LEDs of Power, TxD and RxD for easy port monitoring and diagnostics
  • Powered by USB port, no external power adapter required
  • Easy plug and play installation and RS-422/RS-485 device connection
  • COM port number assigned can be changed to any COM port number required
  • Works with USB 1.1 & 2.0 host port


57mm x 76mm x 23mm (with DIN rail bracket)

OS Support:

Windows 98, Me, XP, 2000, 2003, CE, Vista, Windows 7, and Windows 8
Linux and Mac OS 10.X

Additional Information

Manufacturer SerialGear
Material Metal
Serial Chip FTDI