I am searching this forum and i can't find how exactly the eventhandler works. How does it know when it's receiving or sending in order to take an action? Think is better to explain what i want.
I want to use the eventhandler in this scenario:
I am using a IDS which is sending information by SMS via smstools. Everything is ok by now, i am receiving what i need.
The problem is that when the smstools is receiving an SMS, i want to check if it's from the correct phone number (mine for example or a list of numbers would be better).
If it's the correct number, i want to see the text (the text will pe simple, like: yes or no) and take an action depending on it.

I will really appreciate any answer.
Thank you!