/telnyx-voice-advanced-javascript

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

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

Telnyx Voice Advanced - JavaScript

Installation

npm install telnyx@6.74.2

Setup

import Telnyx from 'telnyx';

const client = new Telnyx({
  apiKey: process.env['TELNYX_API_KEY'], // This is the default and can be omitted
});

All examples below assume `client` is already initialized as shown above.

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:

try {
  const result = await client.messages.send({ to: '+13125550001', from: '+13125550002', text: 'Hello' });
} catch (err) {
  if (err instanceof Telnyx.APIConnectionError) {
    console.error('Network error — check connectivity and retry');
  } else if (err instanceof Telnyx.RateLimitError) {
    // 429: rate limited — wait and retry with exponential backoff
    const retryAfter = err.headers?.['retry-after'] || 1;
    await new Promise(r => setTimeout(r, retryAfter * 1000));
  } else if (err instanceof Telnyx.APIError) {
    console.error(`API error ${err.status}: ${err.message}`);
    if (err.status === 422) {
      console.error('Validation error — check required fields and formats');
    }
  }
}

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)

const response = await client.calls.actions.joinAIAssistant('call_control_id', {
  conversation_id: 'v3:abc123',
  participant: { id: 'v3:abc123def456', role: 'user' },
});

console.log(response.data);

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

Update client state

Updates client state

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

const response = await client.calls.actions.updateClientState('call_control_id', {
  client_state: 'aGF2ZSBhIG5pY2UgZGF5ID1d',
});

console.log(response.data);

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)

const response = await client.calls.actions.startConversationRelay('v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ');

console.log(response.data);

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)

const response = await client.calls.actions.stopConversationRelay('v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ');

console.log(response.data);

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)

const response = await client.calls.actions.sendDtmf('call_control_id', { digits: '1www2WABCDw9' });

console.log(response.data);

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)

const response = await client.calls.actions.startSiprec('v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ');

console.log(response.data);

Returns: `result` (string)

SIPREC stop

Stop SIPREC session. **Expected Webhooks:**

• `siprec.stopped`

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

Op