A communication unit for an electrical machine, in particular a hand-held machine tool, includes at least one electrical actuator, a control unit configured to control the at least one electrical actuator, and a receiving unit assigned to a mobile or stationary unit. The at least one electrical actuator and the control unit together form a transmission unit. The transmission unit is configured to transmit data, and the receiving unit is configured to receive the data. The receiving unit includes at least one microphone. To transmit data, via the transmission unit, the control unit is configured to trigger the electrical actuator to generate an acoustic signal that is detectable by the at least one microphone.