USB ⇔ RS-422/485
Interface Converter


●3000 High-voltage Resistant Isolation type
●SI-35USB-2 is smaller than SI-35USB by 20% and supports the demand for space-saving.
●USB Bus power. No need to have an external power supply.
●Virtual COM port driver supporting WindowsR 10 is attached.
●Card-case sized, metal enclosure, noise resitance.
●Able to mount on 35mm DIN rail.
●Lowe power consumption.
●Support 300bps up to 3Mbps.
●Support RS-485 driver control automatically and DTR/RTS line control.
●Monitor RS-485 line and support flow control on CTS line.
●Able to control 128sets maximum as RS-485 multi-drop type.
●Able to extend RS-422/485 up to 1.2Km.

SI-35USB/SI-35USB-2 are USB converter, which converts USB of PC into RS-422/RS-485. 3000V high-voltage resistant isolation ensures the connection between USB and RS-422/RS-485. Supporting wide range of temperature, metal enclosure, and noise resistant make it possible to use in the factories or inspection lab.


< Size Comparison >

■Block Chart
■Appearance (SI-35USB-2)

The images after the 3rd image are CAD data image.


RS-422/485 terminal

5 terminals, easy to wire in the site

Terminal Name RS-422(Full duplex)*1 RS-485(Half duplex)*1
I/O*2 Explanation I/O*2 Explanation
1 TR+ O Transmission data+ I/O Send/Receive data+
2 TR- O Send data- I/O Send/Receive data-
3 GND - Signal ground*4 - Signal ground*4
4 R+ I Receive data+ - No*3
5 R- I Receive data- - No*3
*1: Able to change by Dip switch. (SW-B)
*2: “O”: Output signal from converter. “I”: Input signal toward converter. “I/O”: Both ways.
*3: Do not connect anything when half duplex.
*4: To prevent damage from high voltage on the device, it is recommended to connect the GND between devices.


Dip switch SW-A
SW1 SW2 SW3 Inner Timer
OFF OFF OFF 1350 More9600
ON OFF OFF 677 More19200
OFF ON OFF 338 More38400
ON ON OFF 169 More76800
OFF OFF ON 85 More150K
ON OFF ON 42 More300K
OFF ON ON 43200 More300
ON ON ON 5400 More2400
SW4 OFF Make the driver to be active when RS-422/485 transmission. (for RS-485)
ON Make RS-422/485 driver to be active when DTR or RTS of virtual COM port is active. (for RS-422)
SW5 OFF Make RS-422/485 to be active by DTR of virtual COM port.
ON Make RS-422/485 to be active by RTS of virtual COM port.


Dip switch SW-B
Set the RS-422/485 communication type and terminal control.
SW Function OFF ON
SW1 Echo reception of transmission data Yes No
SW2 Communication type Half duplex Full duplex
SW3 TXD Terminal resistor Open 100Ω
SW4 RXD Terminal resistor Open 100Ω

< Mounting on the DIN rail >

Screw on the bottom using the M3 screw.