Utilities for running 433 MHz dirt cheap rf-link devices from a Raspberry-Pi. Especially for the Nexa remote protocol.
One program (rx433) listens and records what a remote control sends when you push a button. It then analyzes and extracts the message. A message is a command intended to be acted on by a remotely controlled device.
Another program (tx433) can take those messages and transmit them.
The net effect is that instead of manual button pushes on your remote you get programmatic control through your Raspberry-Pi.