[USB-304] 2 channel USB RS485/422 Converter (Independent Isolation) HuMANDATA LTD.

[USB-304] 2 channel USB RS485/422 Converter (Independent Isolation) MAX 12Mbps

RoHS10 8ch RS485 RS422 TB HI-SPEED Isolated SurgeProtection DMX512
NonChemi-Con Flame-retardant-ABS

2 channel USB RS485/422 Converter
Each 2 channels are independent isolation

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 USB-304 is a 2 channel USB to RS485/RS422 converter that isolated between each RS-485/422 serial port and a USB port. You can use 2 channels of RS-485/422 serial port from a USB port. Those 2 channels are isolated independently from USB side.
USB-304 has the dip switch to enable and disable the built-in 120 ohm terminal resistor. This is designed around the high performance industry proven FTDI chipset.



  • Supports RS-485/RS422
    2-wire or 4-wire of RS-485/RS422 selectable by the dip-switch
  • Each 2 channels are independent isolation
  • 2000VDC bus isolation
  • Baud rate up to 12Mbps (RS422)
    • The built-in isolator IC is available for up to 16Mbps
    • There is a baud rate that can not be set at more than 6Mbps.
    • RS-422 mode: up to 12Mbps, RS-485 mode: up to 6Mbps
  • Supports custom baud rate
    *When baud rates are more than 6Mbps, only 8 Mbps or 12 Mbps are supported. Please feel free to ask us about that by an inquiry form or e-mail.
  • USB 2.0 High Speed (480Mbps) and Full Speed (12Mbps) compliant
  • Auto transmit data control
    Built-in USB-serial chip has auto transmit controller and the driver is activated when it transmit the data
  • Built-in fail-safe bias resisters
  • Built-in 120 ohm terminal resistor selectable by the dip-switch
  • Pluggable the screw terminal
  • No external power supply is required
    USB-304 is powered through a USB port (Bus-powered)
  • Reliable industrial grade design
  • ESD and surge protection
  • Housing material: Plastic
  • DIN rail and screw mountable (Attachment is required)
  • Includes a USB cable (1.8m)
  • Includes an AC adapter
  • Non-use of 10 Restricted substances of RoHS directive


Item Description Remarks
Model USB-304  
Input Power DC 5V / Less than 200mA
Supplied through a USB port
No external power supply required
Number of RS-485/422 Port 2  
I/O Interface RS-485/422 (2-wire or 4-wire) ESD protection 
HOST Interface USB 2.0 compliant (Support Hi Speed) USB 1.1 compatible ESD protection 
USB Connector USB B type (Female)  
Isolation Method Bus Isolation  
Isolation Protection Over 2000VDC Designed value
Processor FT2232H FTDI
USB Driver Virtual COM port driver  
Baud Rate 300bps to 6M/8M/12Mbps Support custom baud rate
Data Bits 7 or 8 bit  
Stop Bits 1 or 2 bit  
Parity Even, Odd or No-parity  
FIFO RX Buffer Size 4096 Bytes / ch  
FIFO TX Buffer Size 4096 Bytes / ch  
RX    :Receive data LED x2
TX    :Transmit data LED x2
RS485/RS422 Connector Detachable the screw terminal 5pin(PHOENIX CONTACT) 3.5mm pitch
Support OS Windows 10/8.1/8/7/Vista/XP  
Operating Ambient Temperature -20 to 60℃ (-4 to 140 [°F]) No condensation permitted
Operating Ambient Humidity 30 to 85%RH No condensation permitted
Storage Ambient Temperature -20 to 60℃ (-4 to 140 [°F]) No condensation permitted
Storage Ambient Humidity 30 to 85%RH No condensation permitted
Weight Approx. 100 [g] Only main body
Dimensions 69 x 82.5 x 30 [mm]
(2.638" x 3.248" x 1.181")
Without projections

* Power saving function (suspend, standby, sleep and others) is not supported

Interface Termianl (RS-485/RS422 PIN ASSIGNMENT)

Pin No Signal Direction Notes

A (RD+)

IN Receive data +

B (RD-)

IN Receive data -
3 GND - Signal ground

Y (SD+)

OUT Transmit data +

Z (SD-)

OUT Transmit data -

Package Contents

  • USB-304
  • USB A-B cable 1.8m
  • Driver & Application CD

Price and Optional Accessories

Description MODEL Image List Price (JPY) Stock Status
2 channel USB RS485/422 Converter USB-304 USB-304
Attachment with clamping screw
PEN-003 PEN-003
Attachment for 35mm DIN rail
Attachment with neodymium magnet
PEN-003-MG PEN-003-MG
Detachable 5P Terminal Connector
1840395 (Phoenix)
(Additional purchase)
TB35-USB-5 TB35-USB-5
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© HuMANDATA LTD. - Altera & Xilinx FPGA Boards manufacturer in Japan - 2016