Serial to Ethernet Converter, 4 ports

USR-N540 is an Industrial Serial to Ethernet Converter to realize bi-directional transparent transmission between RS232/RS485/RS422 and network with function of modbus gateway.

  • 4 serial ports, each one can select RS232/ RS485/RS422
  • Hardware Watchdog, keep to work stable
  • Modbus RTU -TCP, Customized webpage, websocket
  • Serial ports can work simultaneously

Work mode

TCP Server
Serial server device USR-N540 listens on the setting port and waits for a TCP client connection. The data which the serial ports sent out transparently transmit to all connected client via serial device USR-N540.

TCP client mode
The serial converter USR-N540 initiates a TCP lint to the set IP address. If the connection fails, USR-N540 will keep trying to reconnect until it succeeds. Once the link is successful, the data will be transparently transmitted between PC and serial device in bi-directional.

UDP mode
Serial server device USR-N540 sent the data to designated IP /Port. If the connection fails, USR- N540 will keep trying to reconnect until it succeeds. Meanwhile, USR- N540 listens the port and forwards all data received to serial device.

HTTPD Client
Support serial data transmitted to designed server in HTTPD way

Supports WebSocket Sever,
Built Websocket link with devices by Websocket of webpage HTML5
Data transmission between built-in webpage and serial port in bi-directional
Custom webpage and websocket are acceptable
Achieves the functions of displaying data in real-time


System Information
Basic Frequency120MHz
Flash512K byte
Port Number
Interface Standard8 pin RJ45
Rate10/100 Mbps MDI/MDIX, auto switch between cross and direct connection
Protection2KV electromagnetism isolation, shell insulation blocking
Network ProtocolIP, TCP, UDP, DHCP, DNS, HTTP, ARP, ICMP, Web socket, Httpd client
Receive BufferMax 16k bytes buffer
Port Number4 (Each port can work as RS-232,RS-485 and RS-422, can work at the same time)
Interface StandardRS-232: DB9 pin type, RS-485: 2 wire (A+,B-), RS-422 (A,B,Y,Z)
Data Bits5, 6, 7, 8
Stop Bit1, 2
Check BitNone, Even, Odd, Space, Mark
Baud Rate600bps ~ 230.4Kbps
BufferSend and receive 2k bytes respectively
ProtectionRS-485: anti-static 2KV, lightning protection
RS-485 Pull-up and Pull-Down Resistor2.2 KΩ
Virtual Serial(USR-VCOM)Windows 2000 or higher (32 bit/64 bit)
ConfigurationBuilt-in webpage, computer set-up software, serial command
Basic Parameter
Size222 x 122 x 29 mm (including shell and terminals)
Operating Temp.-40 ~ 85°C (industry)
Storage Temp. -40 ~ 85°C, 5 ~ 95% RH (no condensation)
Input VoltageDC 5 ~ 36V
Working Current53mA @ 12V
Warranty2 years

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