ESPHome adds simultaneous recording and playback for devices whose microphone and speaker share one I²S digital audio port. Previously, starting one side locked out the other, preventing a device with a single audio codec from recording while it played sound.
Remco van Essen adds an optional full-duplex configuration with matching audio clocks and formats. It supports a standard microphone and speakers using an external digital-to-analogue converter; multiple speakers can share the connection, but only one plays at a time. Resamplers can adapt the shared format for voice processing or incoming music.