Two-Port USB to Serial RS-232/422/485 Adapter


Main Features:

  • Serial adapter for USB 1.1 and 2.0 port hosts
  • Two serial ports—field selectable RS-232/422/485
  • Small, (4" x 4" x 1.8") rugged industrial enclosure
  • PC/104 module size and mounting compatibility
  • Speeds up to 921.6Kbps
  • Power and individual port activity LEDs
  • All required power drawn from USB port, no external power adapter required
  • Extra downstream USB expansion port
  • Type B USB connector features industrial strength and high-retention design


Factory Options:

  • OEM (board only) version with PC/104 mounting holes and PCB footprint for added flexibility in embedded applications
  • DIN rail mounting provision for industrial environments






Connector Pin Assignments:

  • USB-COM-2SM has two 9-pin connectors for the serial ports.


Communications Interface:

  • I/O Connections: There are 9 pins per port including common grounds. All RS-232 signals are supported and present at the DB9 connectors.
    • RS-422 data signals – Tx+, Tx-, Rx+, Rx-, GND
    • RS-485 data signals –
      • 2 wire: Tx/Rx+, Tx/Rx-, GND
      • 4 wire: Tx+, Tx-, Rx+, Rx-, GND
      • Jumper selectable termination
  • Serial Data Rates:
    • Up to 230.4K bps, asynchronous for RS-232
    • Up to 921.6K bps, asynchronous for RS-422 and RS-485
  • Multidrop: Compatible with RS-485 specifications. Up to 32 drivers and receivers allowed on line. Driver / Receivers used are type SP491.
  • Character Length, Parity and Stop Interval: 5,6,7, or 8 bits; Even, odd, or none; 1, 1.5, or 2 bits
  • Receiver Sensitivity: ±200 mV differential input
  • Common Mode Voltage: +12V to -7V
  • Transmitter Output Drive: 60 mA with thermal shutdown
  • Termination: Jumper selectable per channel for RS-485 mode
  • Bias: On-board from factory on transmit lines for RS-485 & RS-422


Bus Type:

  • USB 1.1 and 2.0 host compatible


Power Required:

  • 5V@ 120mA maximum
  • 0-60mA for each COM channel
  • +5VDC provided via USB cable up to 500mA



  • Operating Temperature Range: 0°C. to +60°C.
  • Storage temperature Range: -50°C. to +120°C.
  • Humidity: 5% to 95%, non-condensing.
  • Size: 4 inches wide by 4 inches deep by 1.8 inches high


Regulatory Compliance:

  • This product is designed to be in full compliance with CE requirements.










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Contact Details

EPS-Tech Ltd.

Industrial park, Tzur-Igal
2 Bazelet St,

Israel, 44862

Tel: +972-9-749-8585
Fax: +972-9-749-8686
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.