Hands-free Telephony =link= -

[ Incoming Far-End Audio ] ──> [ Vehicle / Room Loudspeaker ] │ (Acoustic Echo Path) │ ▼ [ Outgoing Clean Speech ] <── [ Acoustic Echo Canceller ] <── [ Microphone Input ] (NLMS / DTD / VAD) 1. Acoustic Echo Cancellation (AEC)

The transition from traditional telephony to hands-free configurations altered how voice signals are captured and delivered. Early implementations relied on primitive hardware switching mechanisms, which often resulted in choppy, half-duplex audio paths where only one participant could speak at a time. hands-free telephony

| Problem | Likely cause | Quick fix | |---------|--------------|------------| | Echo / feedback | Mic picking up speaker audio | Reduce speaker volume; move mic away from speaker | | Call drops after 30s | Bluetooth HFP connection timeout | Re-pair device; disable battery optimization for BT app | | Poor voice clarity | Narrowband codec (CVSD) | Switch to wideband (mSBC) if supported | | Can't answer calls by voice | Voice assistant not enabled for calls | Check assistant settings & “Always listening” option | | Wind/road noise on mic | No physical wind protection | Use external mic with foam cover; enable noise suppression | [ Incoming Far-End Audio ] ──> [ Vehicle