How to use voice messages with OpenACP?

[psychomafia-tiger]

Can I send voice messages to control AI agents through OpenACP? How do I configure speech-to-text and text-to-speech?

[psychomafia-tiger]

OpenACP supports sending voice messages to control AI agents and receiving spoken responses.

Speech-to-Text (STT): Uses Groq — requires an API key.
Text-to-Speech (TTS): Uses Edge TTS — free, no API key needed.

Configure voice in ~/.openacp/config.json:

{
  "speech": {
    "stt": {
      "provider": "groq",
      "providers": {
        "groq": {
          "apiKey": "YOUR_GROQ_API_KEY"
        }
      }
    },
    "tts": {
      "provider": "edge-tts"
    }
  }
}

Voice mode has 3 states:

• off — TTS disabled
• next — TTS for next message only
• on — TTS always on

When TTS is enabled, the agent automatically includes a [TTS]...[/TTS] block with a spoken-friendly summary. TTS limit: 5000 characters, timeout: 30 seconds.

You send a voice message on Telegram → OpenACP transcribes via Groq → sends text to agent → agent responds → OpenACP converts to audio and sends back.

Related: Voice & Speech · Configuration Schema

[pchero]

Great breakdown of the Groq STT + Edge TTS pipeline for Telegram voice messages!

For anyone looking to extend this pattern beyond Telegram to actual phone calls (SIP/PSTN), the same concept applies but you need a telephony layer in between. This is where something like VoIPBin comes in — it is an open-source CPaaS built specifically for AI agents over phone calls.

The architecture maps cleanly onto what OpenACP already does:

OpenACP (Telegram)	VoIPBin (Phone/SIP)
Telegram voice → Groq STT	PSTN call → VoIPBin STT
Text → Agent	Text → Agent via webhook
Agent reply → Edge TTS	Agent reply → VoIPBin TTS
TTS audio → Telegram	TTS audio → Phone call

Key differences for telephony use cases:

• No phone number required to start: VoIPBin gives you a Direct Hash SIP URI (sip:direct.<hash>@sip.voipbin.net) for testing without provisioning a DID
• Headless signup: POST /auth/signup returns an access key immediately — no OTP, same philosophy as OpenACP config-based setup
• Media offloading: your agent only handles text, VoIPBin handles RTP/VAD/STT/TTS — similar to how OpenACP abstracts the voice pipeline

Quick example with the Go SDK:

import voipbin "github.com/voipbin/voipbin-go"

client := voipbin.NewClient("your-access-key")
call, err := client.CallCreate(ctx, voipbin.CallCreateRequest{
    Source:      "sip:direct.myagent@sip.voipbin.net",
    Destination: "+15551234567",
})

Docs: https://voipbin.net/skill.md — could be a useful reference if you ever want to add a phone call channel alongside the Telegram voice channel.