Ethernet Modbus Gateway EMB-02R

Ethernet Modbus Two Port Modbus/TCP to Modbus RTU and Modbus ASCII Gateway

  • RoHS Compliant Modbus ethernet gateway
  • Enable serial Modbus devices to communicate with a Modbus/TCP host computer
  • Configuration via Browser, telnet or serial port
  • SNMP agent functionality
  • Protocol aware: minimum configuration needed
  • Two serial ports that each support RS-232, RS-422, RS-485 2 or 4 wire
  • RS-422/485 version with optical isolation available
  • 10 or 100 Mbps ethernet
  • RS-232 interface speeds to 230 Kbps
  • RS-485 Bus mastering for two independent poll strings
  • DIN rail or wall mounting


Indicators (front panel)
Lan Connection
Data Port





The EtherModbus gateway allows serial Modbus RTUs to communicate and interoperate with Modbus/TCP based controllers. The Modbus standard protocol is an asynchronous protocol designed to connect directly to computer asynchronous ports. Modbus has been extended to operate over ethernet using the IP protocol suite. This gateway converts between the Modbus TCP/IP protocol and Modbus ASCII/RTU protocols transparently. The EMB-02 enables one or more MODBUS controllers to communicate with MODBUS ASCII/RTU based serial RTUs. It will not allow Modbus/TCP RTUs to operate with a serial MODBUS controller.

The Ethernet Modbus gateway contains two independent serial ports. Each may be configured as RS-232, RS-422, or RS-485 (2 or 4 wire). When configured for RS-485 4-wire, multiple RTU polling strings may be polled on each interface.

For other applications (point-to-point direct RS-232 links or point-to-multiple-points dialed links ) see the EtherPath single port serial server. The EtherPath uses TCP/IP.

A companion product, the EtherPoll is appropriate for applications using other protocols. The EtherPoll is protocol independent, and requires no knowledge of the RTU protocol. This allows it to work with any asynchronous byte-oriented protocol with no additional configuration. The EtherPoll uses UDP/IP. It's data sheet is here.

The EtherGate is another companion product that is protocol-aware. It enables serial SCADA devices to communicate via an ethernet network. The EtherGate is ideal for transporting SCADA protocols via ethernet. To transport SCADA protocols over Frame Relay circuits (without ethernet), use the DCB BPF Scada-FRAD.




Six LEDs indicate LAN and port status


Press button for configuration

Data Port


  • Two serial ports, DE-9 (commonly known as a DB-9 PC connector) DTE interface, individually configurable
  • RS-485 two or for wire interfaces (with bus-mastering on the 4-wire)
  • Serial speeds from 300 bps to 230,000 bps

    LAN Connection

    Interface: 10/100BaseT autoselected


    Front view
    RS-232/422/485 Connector

    Rear view
    LAN and power Connectors

    Front view of Isolated Version



    Need it fast?  Buy on-line or call toll free 800-432-2638!

    Item Number Description Price Buy Now!
    EMB-2R EtherModbus; Dual Port RS-232/485/422 Modbus/TCP to serial Modbus gateway
    (5-30VDC and 120 VAC power supply)
    $595 Qty:
    EMB-2R-I EtherModbus; Isolated RS-422/485 Dual Port Modbus/TCP to serial Modbus gateway
    (5-30VDC and 120 VAC power supply)
    $695 Qty:
    9501033 Optional 36-72 VDC Input Power Supply $ 75 Qty:
    9501081 Optional 125 VDC Input Power Supply $ 125 Qty:
    9902090 Optional DIN rail mounting clips $ 5 Qty:

    Data Comm for Business Inc.
    2949 County Road 1000 E
    Dewey, Il 61840
    Voice: 217-897-6600
    Toll Free: 800-4-DCB-NET
    Toll Free: 800-432-2638
    Email: Contact Page
    Fax: 217-897-8023
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    EtherPath®, EtherSeries®, EtherPoll®, EtherBridge® and EtherModem® are Registered Trademarks of Data Comm for Business, Inc.