In one embodiment, a requesting device (e.g., head-end application) requests a phase-related response from an end-point that does not know its phase in a polyphase power source system. In response, the requesting device receives the phase-related response from the end-point, where the response relays an identification of the end-point and related phase information without indicating an actual phase of the end-point, e.g., on which power-line is a response generated or at which time is a zero-crossing of the power source's waveform. The phase information of the phase-related response may then be correlated to a known phase of a known-phase device, such that the actual phase of the end-point may be identified based on the correlation.