Tunnel – Advanced 4G-RS232 Tunnel – Setting up the MTX Tunnel as a permanently connected TCP/IP Server and configured to send the IP address to a web server by HTTP

Scenario details:

• We need to monitor 100 devices with an RS232 port (115200.8.N.1 and HW flow control) from a central control station using a GPRS link. This will be done using the MTX-Tunnel acting as a transparent serial – 4G tunnel
• Access to the RS232 remote devices at any time is mandatory, so the modem connected to the serial port device (which needs to be controlled) must remain permanently connected to 4G waiting for a connection. Access to the modems must only be allowed for the IP coming from the PC Control (200.200.200.200) and also for a backup IP coming from the central office fiber line, whose IP is: 200.200.200.201
• In order to reduce costs, SIM cards will use dynamic IP addressing. As we have a large number of modems, we will not use DynDNS. So MTX Tunnel will send the IP every time that it the WEB server has been assigned a new one by HTTP (the IP address value assigned by the GSM operator). Every time a modem changes the IP address, the modem must send the new IP address value to the control centre (with URL http://www.miweb.com/datosIP.asp and port 8080). This way the external WebServer will store the IP in a SQL server database so the PC control centre has access to the devices at all times

Solution: MTX-Tunnel firmware + MTX-Java-IoT/MTX-Java-T/MTX-Java-T2

Config.txt configuration file:

Details:

• Bear in mind that when using HTTP, if you use a TCP port different to the standard HTTP (TCP 80), the port must be included in the parameter “DNS_server” and not in “DNS_port”
• Each time MTX-Tunnel changes the IP address, it will connect through and use the following URL: http://www.miweb.com:8080/datosIP.asp?IMEI=&PASS=12345678&IP=
• The web server will receive the parameters sent by the MTX-Tunnel and store the IP address in a database. You can collect the parameters from the ASP page by inserting this example code in “datosIP.asp”.

<%
IMEI=Request.QueryString (“IMEI”)
Password=Request.QueryString (“PASS”)
IP=Request.QueryString (“IP”)
%>

• If you prefer (recomended), you can send data to the server in JSON format via GET or POST. For example, if you wanted to send data in JSON format via HTTP GET, you would have to modify  the configuration with something like this:

• And to send data in JSON format via HTTP POST you would have to modify the configuration the following way:

• When your modem is configured in getjson / postjson mode it will send a JSON with the following format:

{“IMEI”:357042060366409,”TYPE”:”DNS”,”P”:”12345678”,”IP”:”88.28.253.206”, “CSQ”:26,”VER”:”9.12”,”AUX”:””,”MOD”:”201”}

Where each parameter is: 

• Remember that you dispose of the configuration parameters DNS_header1, DNS_header2, DNS_header3 if you want to add headers to your HTTP requests