The latest version of xMasterSlave is 2.2014.10.10 -- Free DNP3 Modbus (Master/Client, Slave/Server and HMI) Software.

Download xMasterSlave and get its registration for free.   Click here to view the screenshot of xMasterSlave.
Click on the link below you can either download xMasterSlave software package: xMasterSlave.zi_p or upgrade to the latest version by Upgrade_xMasterSlave_To_2.2014.10.10.ex_ (change the name to *.exe).
To install it, change *.zi_p to *.zip and unzip and find and run Install_xMasterSlave.exe.
xMasterSlave supports Master and Slave End protocols of DNP3, DNP3 TCP/IP, IEC60870-5-101/103/104, Modbus, Modbus TCP/IP, Modbus Plus, etc. 
xMasterSlave HMI application provides process monitoring, visualization and control, data logging and graphic display, historical trending, alarming, recipe handling, data archiving and much, much more in one complete package. Read the Highlights.
xMasterSlave also can be a Simulator of Master and Slave (i.e. DNP3, Modbus, IEC60870-5, etc.). Slave simulator offers you Hand-free commissioning, Controls(DO&AO)-Details/Action/scripts, Auto/Manual Data Presetting, Log/Protocol Messages and Raw Rx/Tx bytes, TCP/IP (or UDP/IP) connections monitoring, RTU functioning(i.e. Control Enable/Disable, Point Online/Offline), etc. Note: it supports up to 32 instances/slaves in a Master Application, supports up to 200 instances/Master-End-Connections in a DNP3 slave application/simulator.
You also can build an Embedded PC based RTU when you configure and run xRTU18 application in xMaster.

please send me the Registration File: software.aut(generated by the x_Master software during the installation) at Note: check blog/email from 6:00 pm to 10:00 pm (UTC-08:00) Pacific Time (US & Canada). Due to the variations of hardware and personal software used on the PC and your experiences on SCADA/RTU/PLC/HMI/protocols, however, support will be provided on a best effort basis only, and will be limited to email Help/Support available at: Public email (i.e. Hotmail, gmail, yahoo, ...) maybe blocked from receiving your registration due to the virus protection. Please use your business/company email. 

Ċ ReadMe.pdf
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Readme file. Revision notes.  78k v. 43 Oct 29, 2014, 11:05 AM T.G. Scada
Ċ Troubleshooting_RTU_Comm.pdf
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How to troubleshoot RTU/SCADA communications and a Quick Start to use xMasterSlave.  1096k v. 2 Oct 30, 2014, 1:31 PM T.G. Scada
If already installed xMasterSlave before, to upgrade to the latest version, download this file and change the name to *.exe and run it.   19934k v. 1 Oct 29, 2014, 11:06 AM T.G. Scada
Ċ xMaster_Manual.pdf
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xMaster user manual. You may read Troubleshooting RTU Comm.pdf first.   4732k v. 4 Oct 30, 2013, 5:13 PM T.G. Scada
xMasterSlave software package. Rename *.zi_p to *.zip. Unzip it into a folder before the installation. The license of xMasterSlave is for free now. If you are the end user you can install any copy you want to. Each installation creates own registration file *.aut and needs to send it to us and get back another registration file *.key. xMasterSlave applicationwill show you unregistered software until you receive and install/copy a pair of registration files (*.aut and *.key). You can find *.aut in the folder of xMasterSlave (working directory: c:\xMaster in default) when you finish the installation.     20730k v. 79 Oct 29, 2014, 11:05 AM T.G. Scada
Ċ xRTU18_Appl_Configuration_Tips.pdf
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Tips of how to configure a xRTU18 application.  10k v. 2 May 29, 2012, 6:28 PM T.G. Scada
Ċ xRTU18_Appl.pdf
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xRTU18 application allow you to build an Embedded PC (i.e Advantech UNO-1172AH, UNO-4863, etc. ref: based RTU. You also can find how to bridge DNP3 controls to xMaster Applications (i.e. Modbus and DNP3). It also easily allow you to make a RTU Interface for PLC-SCADA system.  4398k v. 8 Nov 13, 2013, 11:11 AM T.G. Scada
Ċ xSlave_Manual.pdf
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xSlave user manual. You may read Troubleshooting RTU Comm.pdf first.  901k v. 12 Oct 30, 2014, 1:31 PM T.G. Scada