IEM308-8D Serial Server Module
  • 2×10/100Base Ethernet Ports, 8×TTL UART Ports
  • Industrial-Grade Embedded Serial Server Module
Features and Benefits
  • Support UDP, TCP, Modbus, HTTPD,WebSocket protocols, support virtual com port
  • Support Modbus slave read-ahead, single-port auto-learn up to 256 RTU or 128 ASCII commands
  • Support Modbus address mapping
  • Support MQTT protocol, realize connectivity between cloud and clients via multiple cloud platforms
  • Support JSON functions
  • Compact design for easy installation, maintenance and PCBA
  • 3.3V supply voltage
  • Work in -40~85℃ industrial working temperature
  • Overview
  • Specifications
  • Downloads
  • Models
Product Description

IEM304-8D is an industrial class embedded serial port server module, integrated serial port device networking, Modbus gateway, and other functions. It has 1*10/100Base Ethernet interface and 4 TTL serial ports. It can be embedded mounted to meet the requirements of various industrial buses or network field.


The server module can be managed via WEB and supports various network protocols, such as IP, ARP, UDP, TCP, ICMP, HTTP, Modbus TCP, Modbus RTU / ASCII, HTTPD, WebSocket, RealCOM, RFC2217, DHCP Client, DNS, etc. Its serial port supports various network transmission modes, such as UDP, UDP Multicast, TCP Client / Server, Pair Connection Master / Slave, Modbus TCP / RTU / ASCII, Httpd Client, WebSocket Client, etc. It supports CAN and serial port interface conversion, and virtual serial port function. The system provides user permission management, supporting online restart, upgrade and factory reset. The 4 port embedded server module supports hardware watchdog, and reset, factory settings restore, designed with indicators. It features low power consumption, wide temperature range, compact modular design. The surface mounted female header is easy to easy and maintain, flexible for PCBA and customize interface connection mode. Developed with industrial components, high performance low power processor, the module can work reliably in multiple harsh environments with -40℃ ~ + 85℃ wide temperature range. The products can be widely used in industrial automation, comprehensive energy, intelligent transportation, smart city, smart mining and other fields.

Features and Benefits
  • Ethernet ports can be configured as two separate network segments or cascaded ports
  • Serial port baud rate 300bps-460800bps 
  • Support UDP Client/ Server /Multicast mode
  • Sepport TCP Client/Server modes, establish sessions via TCP protocol, TCP Client supports up to 16 session connections, TCP Server supports up to 32 session connections, serial port baud rate and other communication parameters can be modified dynamically via RFC2217 instruction
  • Support Pair Connection Master/Slave mode
  • Support Modbus RTU/ASCII Master/Slave modes to realize conversion from Modbus TCP to Modbus RTU/ASCII
  • Support RealCOM_MCP/CCP/MW modes, mapping network to local COM
  • Support HTTPD Client mode, GET or POST operations can be performed with HTTPD servers
  • Support WebSocket protocol
  • Support serial port forwarding, realize transparent data transmission between serial port and other serial ports, provide one-way forwarding/receiving, two-way forwarding direction control
  • Support multiple data packaging mechanism to enable time or length based data conversion from serial to Ethernet
  • Support serial port data frame filter based on start and end bytes of the frame
  • Support registration package and heartbeat package for verification and status check of the link
  • Support Modbus virtual ID, mapping Modbus slave real ID to virtual ID for data communication, avoiding slave ID duplication
  • Support DES/ 3DES/ AES/ RC2/ RC4/ RC5/ BlowFish and multiple encryption for data security
  • Support SSL (TLS1.0/1.1/1.2) encryption, one-way/two-way verification for link security
  • Support HTTP/ HTTPS/ SSH/ TELNET access control, and IP/ MAC address filter
  • Support alert for reboot, login events, configuration change, password change via email and SNMP
  • Support serial port and CAN port communication parameters, working mode, send and receive frame counts
  • Support local log storage, network storage and serial port log output
  • Support serial port restart, device reboot/upgrade, factory reset, and NTP client


Working Mode

Support Modbus RTU Master, Modbus RTU Slave, Modbus ASCII Master, Modbus ASCII Slave, UDP Client, UDP Server, UDP Multicast, TCP Client, TCP Server, RealCOM_MCP, RealCOM_CCP, RealCOM_MW, Pair Connection Master, Pair Connection Slave, HTTPD Client, WebSocket Client, MQTT modes

Support serial to serial port data forward

Support SSL encryption, data encryption, transparent transmission/JSON transmission

Support Modbus slave virtual address, Modbus readahead, Modbus address mapping batch read/write

Support Keepalive, heartbeat package, registration package, head and tail of a frame, RFC2217

Secure Management

Support password setting

Support WEB/ SSH/ TELNET/ HTTPS access control

Support IP/ MAC address filter

Support alert via Email and SNMP

Support certificate upload

System Management

Support device information, serial port information statistics

Support independent segment or cascade mode, static address/DHCP

Local sys log, remote lot, export log via Serial Port

Support SNMPv1/v2c/v3

Support serial port restart, connection reset after idle for some time

Online reboot, upgrade and factory reset

Support NTP



2×10/100Base-T(X) auto-sensing Ethernet pin, full/half duplex, auto MDI/MDI-X connection, 1.5 kV isolation protection, built-in Ethernet transformer


Number: 8

Type: 3.3V TTL UART (use an external serial port chip to get the extra RS232/485/422 COM port you need)

Baud rate: 300bps-460800bps

Data bit: 7bit, 8bit

Stop bit: 1bit, 2bit

Parity bit: None, Odd, Even


RS232 signal for debugging and command line configuration

Status LEDs

Support the RUN, Ethernet port Link/ACT, Ethernet port Speed, serial port indicator pins

Power Supply

Input Voltage

DC 3.3V±3%

Power Consumption

1W@DC3.3V(full load)


2×1.27mm pitch 2*25P surface mounted female header (pins included)

Physical Characteristic


55×40×9.9 mm


Embedded mounted



Working Environment

Operating Temp


Storage Temp


Relative Humidity

5%~95% (non-condensing)

Industry Standard







Version 1.1

Standard Model

10/100M Ethernet Port


Input Voltage




DC 3.3V±3%

Subscribe to Newsletter
Copyright © 2024 Maiwe Communication All rights reserved.