The Kasten 22 is the microphone and headphone connection box for the Panther's gunner. The headphone jack has two pins: one for the signal and one to ground. The microphone jack also has two pins: one for the signal, and one to ground. The gunner cannot connect to the radio operator, or use the radio station unless the commander directs the radio operator to switch the Kasten 20 to the Funk und Bord position.