This time I used my two channels for Dot Contact Closure (red) and for Dash Contact Closure (yellow). Unfortunately the side-tone signal is not recorded, but you can hear the sound to confirm that the letter R is generated.
This is a SYNTHESIZED image to emulate a 3-channel oscilloscope. From the top, the signals are the Dot Contact Closure (red), the Dash Contact Closure (yellow), and the side-tone (green), respectively. The synthesis of two images is justified because the side-tone for the letter R is (or should be) always the same.