Several years ago back in 2013 and 2014 we uploaded two posts showing how it was possible to use an SDR to listen in to restaurant pagers and collect data from them, and also to spoof their signal and activate them on demand. If you were unaware, restaurant pagers (aka burger pagers), are small RF controlled discs that some restaurants hand out to customers who are waiting for food. When the food is ready, the pager is remotely activated by the staff, and then flashes and buzzes, letting the customer know that their order can be picked up.
Over on YouTube user Tony Tiger has uploaded a video that shows an overview on how to reverse engineer the signal coming from a particular brand of restaurant pagers. The tools he uses include a HackRF SDR and the Inspectrum and Universal Radio Hacker software packages. If you're interested in reverse engineering signals, this is a good overview. Later in the video he shows a GNU Radio and Python program that he's created to control the pagers.