Voice Intercom and VoIP
Introduction
The voice-intercom and VoIP solution runs pickup, 3A processing, and the call protocol on ESP32 / ESP32-S3, without a separate DSP. The path can be SIP/VoIP on a LAN or the internet, or a carrier number for real inbound and outbound calls. It supports full-duplex one-to-one calls and multi-party conferences. Adding a camera extends it to a video call.
Near-field intercom does not need long pickup range: one microphone plus an audio codec is enough. Conference or far-field products can use a 1-to-3-mic array.
flowchart LR
Mic["Microphone"]
Afe["NS and AEC"]
Sip["SIP or VoIP"]
Spk["Speaker"]
Mic --> Afe
Afe --> Sip
Sip --> Spk
Applications
Smart devices: hands-free calling inside a speaker, appliance, or voice door lock
Care and emergency: one-button help terminal or care alarm, connecting to a care desk or a designated number
Conference and field work: conference phone; hands-free terminals for riding or delivery
Child care: voice calling on a story player or care device, optionally with video
Features
SIP/VoIP network calls, plus carrier-number dialing and answering
Full-duplex audio with noise suppression (NS) and acoustic echo cancellation (AEC)
One-to-one calls or multi-party conferences
Near-field single microphone, or a 1-to-3-mic array
Optional voice assistant or simple display (HMI)
Hardware and software
A common SoC is ESP32-S3; use ESP32-S31 when classic Bluetooth is required. The audio front end is in ESP-SR. SIP and related protocols are in ESP Media Protocols. An example is adf_examples/protocols/voip.