In this blog we are going to learn how to configure the TRB140 to change the state of an I/O via SMS. This is very handy for many situations, including remote control of relays for waterpumps, lights, motor controllers, etc. 

Initially we need to ensure that the SIM is working - For troubleshooting a 3G/4G connection see this blog here: 

Now that we have a solid connection to your ISP, we need to set some SMS rules. Navigate to Services > Mobile Utilities > SMS Utilities. 

From here, for testing purposes, we can just edit an existing rule - This time I am going to edit the Reboot rule, by clicking the pencil. 

From here we just need to change the action to "Change I/O state". In the I/O field, change the pin that you want to change the state of (3 or 4) - The next step is to chose whether you want to change the state to high or low. I have set the SMS text to "IOHigh", as I want to change the state to high, when setting your SMS message, don't use spaces between words, otherwise you may run into issues. Lets look at Authorization next. 

There are many different configurations for authorization rules, you can find a full list of detailed explanations on how to configure the rule and what each of the fields mean : . For testing purposes however, we can go ahead and select no authorization and allow all numbers. This should be all we need for this setup. I have sent the message "IOHigh" to the number associated with the SIM in the TRB140, and the state changed from Low to High. 

We can obviously achieve the same in reverse, changing from High to Lo. All we need to do is change the state when modifying the rule. 

For more information check out the Teltonika Wiki :