USB to RS-422/485 isolation voltage is 3kVdc
[ Composition ]

Converter: 1
USB cable: 1
Utility CD: 1
Instruction Manual: 1 ( in Japanese only)

Warranty: 1


[ CASE ]

Where SI-series are used.

SI-35USB is an 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.

PANASONIC recommends using SI-35USB as a connection between PC and the Eco-Power Meters.
[Connection Image]



  1. RS-422/485 terminal block.
  2. USB connector
  3. Power LED
  4. Data status LED
  5. Dip Switch A *1
  6. Dip Switch B *2
*1:Set the RS-422/485 driver control and inner timer for line monitor.
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.
*2: 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
Pin Assignment
Terminal # Name RS-422(Full duplex)*1RS-485(Half duplex)*1
I/O*2 Explanation I/O*2 Explanation
1 TR+ O Transmission data+ I/O Transmission/Reception data+
2 TR- O Transmission data- I/O Transmission/Reception data-
3 GND - Signal ground*4 - Signal ground*4
4 R+ I Reception data+ - No*3
5 R- I Reception 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.
< Mounting on the DIN rail >
Screw on the bottom using the M3 screw.


Conversion USB⇔RS-422/485
USB Interface USB1.1/2.0, full speed transmission B connector
LED Transmission: TXD, Reception: RXD, Power: PWR
Serial Interface RS-422/485, Full duplex/ Half duplex
5 pole terminal block (press-to-screw pitch type)
Fitness wire: AWG24-14*1
Serial Signal TXD, RXD or TXD/RXD
Asynch type Asynch
Baud Rate 300bps to 3Mbps*2
Data Frame Data bits[7or8] + Parity[Even/Odd/none] + Stop bits[1/2]
Flow Control Xon/off, RTS/CTS (supported by COM port emulator)
RS-485 Monitor Monitor non-communication on RS-485*3
RS-485 Driver Control Control RS-485 driver to be active. (for transmission only)*4
Multi-drop connection Max. 128 sets
Mounting method Using M3 screw hole in the bottom face, installation to a DIN rail (SI-DIN70 is required.)
Signal Isolation Protection 3000Vdc
System requirements
(USB equipment)
PC: PC/AT compatible with USB port (DOS/V PC)
OS: Windows® 7/8/8.1/10
Power USB Bus power, DC5V±10%, Max. 250mA
Power Consumption 1.3W or less
Temperature In operation: -10 to 55°C, In storage: -20 to 75°C

In operation: 10 to 90%RH

In storage: 10 to 90%RH (No condensation)
Dimension 65(W)×90(D)×22(H)mm
Weight Approx. 200g
Composition USB cable (1.8m), Utility CD, Instruction manual (in Japanese only), Warranty.
*1: Single wire: 0.2-2.5 mm2. Stranded wire: 0.2-1.5 mm2.
*2: Speed is established in application software. Certain speed beyond 1.2Mbps cannot be established.
*3: Half duplex RS-485 communication requires data transmission while none of other equipments transmit data on RS-485. SI-35USB monitor function sends signal to CTS of the virtual COM port, when designated non-communication period was detected. By this, communication control precession in the PC side is simplified.
*4: Half duplex RS-485 communication needs to activate RS-485 driver only to transmit data. SI-35USB driver auto-control activates the driver IC on the top of transmitted data, and makes it to be non-active after the last data automatically.
*5: Supports 32bit/64bit of Windows 7/8/8.1/10