If you have an older Raspbian image then these instructions may work for you.
The Raspberry Pi uses the serial port as a monitor, by default, so you will need to disable this so that you can use the serial port for the base station receiver.
Run the Raspberry Pi configuration tool to disable the serial port:
Select the Advanced Options menu option,
Followed by Serial menu option,
then select NO to the question "Would you like a login shell to be accessible over serial?".
Exit save and reboot.
Special instructions for Raspberry Pi 3 only:
The Raspberry Pi 3 has had some issues with the workings of the serial port and has had a number of changes to the operating system since its release. Here is the latest information we have on how to configure the Raspberry Pi 3 to work with the RF Base Station:
Add the following lines:
Exit, save and reboot.
sudo nano rfsensor.py
Then change the following line: