Systems, devices and techniques disclosed in this document provide device-to-device communications via a human body of a user between (1) a capacitor sensor touch screen device that includes a capacitor sensor touch screen that includes capacitor sensors and provides a display function and (2) a capacitor sensor device that includes one or more capacitor sensors that detect or sense, based on capacitive sensing and without providing a display function, signals transmitted from the capacitor sensor touch screen of the capacitor sensor touch screen device. The human body of a user operates as a signal transmitting medium. In addition, the systems, devices and techniques disclosed in this document provide device-to-device communications via direct device-to-device coupling between two capacitor sensor touch screen devices each including capacitor sensor touch screen that includes capacitor sensors and provides a display function.