According to various examples, alternator controllers, systems for communicating with an alternator controller and methods for communicating with an alternator regulator are described herein. As an example, the alternator controller includes an input terminal configured to be coupled to a coil of a stator of an alternator and an interface circuit coupled to the input terminal and configured to convert a multi-valued signal at the input terminal into parallel signals. According to another example, a system for communicating with an alternator controller is described herein. This example includes a device and an alternator controller. The device includes an encoder. The alternator controller includes a decoder and at least one phase terminal. The encoder and the decoder are coupled via the at least one phase terminal of the alternator controller.