Serial converters for industrial use

Our USB to RS485 converters 

We are specialized in making converters for usb, RS485, RS232 and RS422, targeting customers who needs converters that have better quality than the cheap un-isolated, but smaller and less expensive than the industrial types of converters.
All our converters are isolated, powered from the usb side, and with virtual comport drivers.

flag Dublin, IrelandJul. 2013
Very satisfied with the service and product supplied by Hjelmslund. Very fast response time, even when we required a special assembly. High quality product, worked excellently first time.

John Clarke - Nines Engineering
Website :

Isolated USB to RS485 converter - USB485-STISO

USB485-STISO  - 2 wire half duplex RS485 converter.

USB485-STISO : USB to RS485 converter with 2500 volt isolation

Connect your control network to the PC with an isolated RS485 converter, using it as a virtual com port.
Its isolation barrier and readiness for Modbus gives it the quality needed for use in industrial automation.
2 wire half duplex w. Automatic Rx/Tx switching and Rx/Tx FIFO for smooth operation - no programming of RTS to set the direction, and no dip-switches.

USB485-STIXL  - as STISO, but larger terminals.

PDF Icon  USB485-STISO/STIXL product sheet

Shopping Buy USB485-STISO Online

Shopping Buy USB485-STIXL Online

Isolated USB to RS485 / RS422 converter - USB485-STI4W

USB485-STI4W  - 4 wire full duplex RS485 / RS422 converter.

USB485-STI4W : Isolated USB RS485/422 converter

Our 4 wire full duplex model of USB to RS485 converters.
The receiver is always enabled, but the transmitter is only enabled during data transmission, thus making it possible to use it even as a slave device.
Drives up to 256 nodes, 1Mbps, 2.5kV isolation voltage.

PDF Icon  USB485-STI4W product sheet

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USB RS485 converter with RJ45

USB485-MB45  RS485 with cable and RJ45 - for Modbus.

USB485-MB45 : Isolated RS485 converter with cable and RJ45 for Modbus

The RJ45 is wired according to the Modbus specifications Ver 1.02   Section 3.5.1

Pin 4 : Data - (B)
Pin 5 : Data+ (A)
Pin 8 : Common

Extremely flexible shielded cable where the shield is connected to Modbus 'common' internally in the converter.
Standard cable length is 3 meter, but 1.5 / 5 / 10 meter versions will be available as well.

PDF Icon  USB485-MB45 product sheet

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Isolated panel mount converters for RS232 & RS485.

Our panel mount converters are ideal for being used in racks and industrial enclosures, to provide easy access to an internal RS232 or RS485 connection from an external USB port. Furthermore it adds a 2.500 volt isolation barrier at the most perfect location - exactly at the border between internal and external circuits.
Powered from USB - no external power supply required.

USB232-ILP : The RS232 version

PDF Icon  USB232-ILP product sheet
Shopping Buy USB232-ILP Online   € 62 @1 / € 55 @10

USB485-ILP : The RS485 version

PDF Icon  USB485-ILP product sheet
Shopping Buy USB485-ILP Online   € 70 @1 / € 63 @10

USB to RS485 converter, isolated panel mount type - USB485-ILP

Isolated panel mount converters for RS485.
USB232-ILP USB232-ILP USB485-ILP mounting example. USB485-ILP mounting example.

Contact info

Updated - 24 April 2014.