/telnyx-voice-advanced-curl

name: telnyx-voice-advanced-curl
description: >-
  Advanced call control features including DTMF sending, SIPREC recording, noise
  suppression, client state, and supervisor controls. This skill provides REST
  API (curl) examples.
metadata:
  author: telnyx
  product: voice-advanced
  language: curl
  generated_by: telnyx-openapi-pipeline

<!-- Auto-generated from Telnyx OpenAPI specs. Do not edit. -->

Telnyx Voice Advanced - curl

Installation

# curl is pre-installed on macOS, Linux, and Windows 10+

Setup

export TELNYX_API_KEY="YOUR_API_KEY_HERE"

All examples below use `$TELNYX_API_KEY` for authentication.

Error Handling

All API calls can fail with network errors, rate limits (429), validation errors (422), or authentication errors (401). Always handle errors in production code:

# Check HTTP status code in response
response=$(curl -s -w "\n%{http_code}" \
  -X POST "https://api.telnyx.com/v2/messages" \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"to": "+13125550001", "from": "+13125550002", "text": "Hello"}')

http_code=$(echo "$response" | tail -1)
body=$(echo "$response" | sed '$d')

case $http_code in
  2*) echo "Success: $body" ;;
  422) echo "Validation error — check required fields and formats" ;;
  429) echo "Rate limited — retry after delay"; sleep 1 ;;
  401) echo "Authentication failed — check TELNYX_API_KEY" ;;
  *)   echo "Error $http_code: $body" ;;
esac

Common error codes: `401` invalid API key, `403` insufficient permissions, `404` resource not found, `422` validation error (check field formats), `429` rate limited (retry with exponential backoff).

Join AI Assistant Conversation

Add a participant to an existing AI assistant conversation. Use this command to bring an additional call leg into a running AI conversation.

`POST /calls/{call_control_id}/actions/ai_assistant_join` — Required: `conversation_id`, `participant`

Optional: `client_state` (string), `command_id` (string)

curl \
  -X POST \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "conversation_id": "v3:abc123",
  "participant": {}
}' \
  "https://api.telnyx.com/v2/calls/v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ/actions/ai_assistant_join"

Returns: `conversation_id` (uuid), `result` (string)

Update client state

Updates client state

`PUT /calls/{call_control_id}/actions/client_state_update` — Required: `client_state`

curl \
  -X PUT \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "client_state": "aGF2ZSBhIG5pY2UgZGF5ID1d"
}' \
  "https://api.telnyx.com/v2/calls/v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ/actions/client_state_update"

Returns: `result` (string)

Start Conversation Relay

Start a Conversation Relay session on an active call. Conversation Relay connects the call audio to your WebSocket so your application can exchange realtime messages with the caller while Telnyx handles speech recognition and text-to-speech. Only one AI Assistant or Conversation Relay session can be active on a call at a time.

`POST /calls/{call_control_id}/actions/conversation_relay_start`

Optional: `assistant` (object), `client_state` (string), `command_id` (string), `conversation_relay_dtmf_detection` (boolean), `conversation_relay_settings` (object), `conversation_relay_url` (string), `custom_parameters` (object), `dtmf_detection` (boolean), `greeting` (string), `interruptible` (enum: none, any, speech, dtmf), `interruptible_greeting` (enum: none, any, speech, dtmf), `interruption_settings` (object), `language` (string), `languages` (array[object]), `provider` (string), `structured_provider` (object), `transcription` (object), `transcription_engine` (enum: Google, Telnyx, Deepgram, Azure, xAI, AssemblyAI, Speechmatics, Soniox, A, B), `transcription_engine_config` (object), `tts_provider` (string), `url` (string), `voice` (string), `voice_settings` (object)

curl \
  -X POST \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  "https://api.telnyx.com/v2/calls/v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ/actions/conversation_relay_start"

Returns: `conversation_relay_id` (string), `result` (string)

Stop Conversation Relay

Stop the active Conversation Relay session on a call.

`POST /calls/{call_control_id}/actions/conversation_relay_stop`

Optional: `client_state` (string), `command_id` (string)

curl \
  -X POST \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  "https://api.telnyx.com/v2/calls/v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ/actions/conversation_relay_stop"

Returns: `result` (string)

Send DTMF

Sends DTMF tones from this leg. DTMF tones will be heard by the other end of the call. **Expected Webhooks:**

There are no webhooks associated with this command.

`POST /calls/{call_control_id}/actions/send_dtmf` — Required: `digits`

Optional: `client_state` (string), `command_id` (string), `duration_millis` (int32)

curl \
  -X POST \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "digits": "1www2WABCDw9"
}' \
  "https://api.telnyx.com/v2/calls/v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ/actions/send_dtmf"

Returns: `result` (string)

SIPREC start

Start siprec session to configured in SIPREC connector SRS.

**Expected Webhooks:**

• `siprec.started`
• `siprec.stopped`
• `siprec.failed`

`POST /calls/{call_control_id}/actions/siprec_start`

Optional: `client_state` (string), `connector_name` (string), `include_metadata_custom_headers` (boolean), `secure` (boolean), `session_timeout_secs` (integer), `sip_transport` (enum: udp, tcp, tls), `siprec_track` (enum: inbound_track, outbound_track, both_tracks)

curl \
  -X POST \
  -H "Authorization: Bearer $