How to time-out a console app?

[lifesgrand]

I am relatively new to the .net stuff, so I'm not even sure what it is I'm looking for. I have a console application that runs unattended in the background (it is being submitted through a third party software) retrieving data from an outside source. Apparently, there is no way for the people sending me the data to identify an end-of-file condition, so I'm basically forced to end the program after a set time of inactivity (30 minutes). How do I do that? Is this even the best option?