USB to RS232/RS422/RS485 converter


The USB Interface model 38211 converts a USB interface into a full-function serial interface. RS232, -422 and -485 devices as well as RS485 bus systems can now be connected through the USB port.

Manufacturer: Wiesemann & Theis / Country of Origin: Germany


  • 1 x USB socket, type B
  • 1 x RS232/422/485
    • 9-pin SUB-D adapter
  • Galvanic isolation between the ports
    • Isolation voltage min. 1kV DC

Management and connectivity:

  • USB 2.0 Full Speed Device (12 Mbit/s)
  • Compatible with RS485 2-wire and 4-wire bus systems
  • Automatic bus access control
  • Common solution for the Windows, Linux and Mac world

Power supply:

  • No additional power supply required
    • Voltage supply via the USB
    • Galvanically isolated power connection
  • Integrated over voltage protection for the serial port

Standards & more:

  • Conforms to standards both in office and industrial environments:
    • High noise resistance for industrial environments
    • Low noise emission for residential and business areas
  • 5 year guarantee


Over voltage protection for serial interfaces
The permissible voltages allowed to have an effect on serial ports in case of an error are limited to rather low values according to the data sheet specifications for the interface components. Voltages which exceed these values even for a short time will inevitably result in damage to or even destruction of the integrated circuits.

To prevent such effects the USB-Interface 38211 includes integrated over voltage protection which uses suppressor diodes to limit the maximum occurring voltages to harmless values in a variety of application situations.

Connections and displays:

  • USB port:
    • Type B female
  • Serial port:
    • RS232/422/485 interface
    • 9-pin SUB-D adapter
  • Operating modes:
    • RS232, RS422
    • RS485 2-wire with automatic control, with and without echo
    • RS485 4-wire with automatic control
  • Baud rate:
    • Standard: 300..115200 baud
    • Configurable: application- and operating system-specific
    • up to 1 Mbaud (RS232),
    • up to 3 Mbaud (RS422, RS485)
  • Data format:
    • Data bits: 7,8
    • Stop bits: 1,2
    • Parity: odd, even, no, mark, space
  • Signal lines:
    • RS232: RxD, TxD, RTS, CTS, DTR, DSR, DCD, RI
    • RS422: RxD A/B, TxD A/B, CTS A/B, DTR A/B (RTS A/B)
    • RS485: RxD A/B, TxD A/B
  • RS485 switching time:
    • A bit time for switching between sending and receiving
  • Termination:
    • Connectable termination network for RS485 operation
  • Overvoltage protection:
    • Limiting of the signal voltages using suppressor diodes
  • Galvanic isolation:
    • Isolation voltage min. 1kV DC between USB and serial connection
    • FTDI FT232R
  • Power supply:
    • 5V DC over USB, optional supply from external 5V power supply
  • Current consumption:
    • Maximum: 200mA
    • Idle: RS232 typ. 70mA, RS422/485 typ. 90mA
  • Displays:
    • 1x LED Data
    • 1x LED On Line

Housing and other data:

  • Housing:
    • Plastic housing for top hat rail installation
    • 105 x 22 x 75mm (L x W x H)
  • Enclosure rating:
    • IP20
  • Weight:
    • approx. 170g
  • Ambient temperature:
    • Storage: -40..+70°C
    • Operating in non-rowed installation: 0..+60°C
    • Operating in rowed installation 0..+50°C
  • Permissible relative humidity:
    • 5..95% RH (non-condensing)
  • MTBF:
    • 358,939h @25°C per MIL-HDBK-217
  • Life expectancy:
    • > 25 years at 25°C ambient temperature
  • Scope of delivery:
    • Interface USB <> RS232/422/485 Industry
    • USB cable with ferrite bead

Product CD with driver and manual in German and English

Weight 0.2 kg