# Download the ofono test scripts and extract
wget https://www.kernel.org/pub/linux/network/ofono/ofono-1.21.tar.gz
tar -xzvf ofono-1.21.tar.gz

# Install dbus, which ofono requires
sudo apt-get install python-dbus

# Plug in the microphone and speaker to the Pi
# Then change the phone number to something 
sudo python ./ofono-1.21/test/dial-number 4045551234
# After you execute the above command, your Bluetooth-connected
# phone will call the specified number.
# Answer that phone and confirm that the payphone handset works