Opto-Isolated USB to RS232 / RS485 / RS422 Converter (Industrial / Por – CommFront
USB Isolator (Industrial) – CommFront
KEPUSHIYE electronic component USB Isolator USB to USB Optocoupler Isolation Module Coupled Protection Board ADUM3160 Isolation Voltage 2500V : Amazon.co.uk: Business, Industry & Science
SP385A-R3, USB to RS232 Opto-Isolated Converter - Black Box