***

id: 524cd0e5-c05c-4f35-8c09-8196255cf38b
title: CallDetect
keywords: >-
SignalWire, Realtime SDK, Node.js, answering machine detection, AMD, fax
detection, call screening
slug: /node/reference/voice/call-detect
sidebar-title: CallDetect
description: >-
CallDetect object reference for detecting call conditions including answering
machines, fax tones, and DTMF digits during voice calls.
max-toc-depth: 3
----------------

[amd]: /docs/server-sdk/v4/node/reference/voice/call/amd

[calldetect]: #

[detect]: /docs/server-sdk/v4/node/reference/voice/call/detect

[detectAnsweringMachine]: /docs/server-sdk/v4/node/reference/voice/call#voice_call_detect_answering

[detectDigit]: /docs/server-sdk/v4/node/reference/voice/call/detect-digit

[detectFax]: /docs/server-sdk/v4/node/reference/voice/call#voice_call_detect_fax

Represents a current or past detecting session in a call.

Obtain instances of this class by starting a Detect session with one of the following methods:

* [`Call.detect`][detect]
* [`Call.detectAnsweringMachine`][detectAnsweringMachine]
* [`Call.detectDigit`][detectDigit]
* [`Call.detectFax`][detectFax]

## **Example**

Detecting answering machines and handling the result:

```js
import { SignalWire } from "@signalwire/realtime-api";

const client = await SignalWire({ project: "your-project-id", token: "your-api-token" });

const call = await client.voice.dialPhone({
  from: "+1xxxxxxxxxx",
  to: "+1yyyyyyyyyy",
  timeout: 30
});

// Start answering machine detection with event listeners
const detect = await call.detectAnsweringMachine({
  timeout: 30,
  initialTimeout: 4,
  endSilenceTimeout: 1,
  machineReadyTimeout: 3,
  waitForBeep: true,
  listen: {
    onStarted: () => console.log("AMD detection started"),
    onUpdated: (detect) => {
      console.log("Detection update:", detect.result);

      if (detect.result === "HUMAN") {
        console.log("Human answered - connecting to agent");
      } else if (detect.result === "MACHINE") {
        console.log("Machine detected - waiting for beep");
      } else if (detect.result === "READY") {
        console.log("Machine ready for message - leaving voicemail");
        call.playTTS({ text: "Hello, this is a message from SignalWire." });
      }
    },
    onEnded: (detect) => {
      console.log("Detection ended with result:", detect.result);
    }
  }
}).onStarted();

// Wait for detection to complete
await detect.ended();
console.log("Final result:", detect.result, "Type:", detect.type);
```

Detecting DTMF digits:

```js
// Detect specific digits pressed during a call
const detect = await call.detectDigit({
  digits: "0123456789#*",
  timeout: 30,
  listen: {
    onUpdated: (detect) => {
      console.log("Digit detected:", detect.result);
    }
  }
}).onStarted();
```

Detecting fax tones:

```js
// Detect if the call is a fax machine
const detect = await call.detectFax({
  tone: "CED",  // or "CNG"
  timeout: 30,
  listen: {
    onUpdated: (detect) => {
      console.log("Fax tone detected:", detect.result);
    }
  }
}).onStarted();
```

## **Properties**

<ParamField path="id" type="string">
  The unique ID for this detecting session.
</ParamField>

<ParamField path="type" type="&#x22;machine&#x22; | &#x22;digit&#x22; | &#x22;fax&#x22; | &#x22;beep&#x22;">
  The type of this detecting session.
</ParamField>

<ParamField path="result" type="string">
  The result of the detecting session. The possible values depend on the detection type:

  | Detect Type                                                        | Event Values                                                                                                                                                                                                                                                                                                                                          |
  | :----------------------------------------------------------------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
  | [`amd`][amd] \| [`detectAnsweringMachine`][detectAnsweringMachine] | **MACHINE**: Machine detected, **HUMAN**: Human detected (final event), **UNKNOWN**: Unknown detection, **READY**: Machine is ready for voicemail delivery (final event if `detect_interruptions=false` or `beep=true`), **NOT\_READY**: Machine voicemail has restarted, interrupting voicemail delivery (only fired if `detect_interruptions=true`) |
  | [`detectDigit`][detectDigit]                                       | Possible digits detected: `0 1 2 3 4 5 6 7 8 9 # *`                                                                                                                                                                                                                                                                                                   |
  | [`detectFax`][detectFax]                                           | **CED**: called station fax tone, **CNG**: calling station fax tone                                                                                                                                                                                                                                                                                   |
</ParamField>

<ParamField path="hasEnded" type="boolean">
  Whether the detection has ended. Returns `true` if the detection is finished.
</ParamField>

## **Methods**

### ended

* **ended**(): `Promise`\<[`CallDetect`][calldetect]>

Returns a promise which will get resolved only after the detecting session is completed.

#### Returns

`Promise`\<[`CallDetect`][calldetect]> - See [`CallDetect`][calldetect] for more details.

#### Example

```js
const detect = await call.detectDigit();
const result = await detect.ended();

console.log("Detect result:", result.type);
```

***

### stop

* **stop**(): `Promise`\<[`CallDetect`][calldetect]>

Stops the detect session.

#### Returns

`Promise`\<[`CallDetect`][calldetect]> - See [`CallDetect`][calldetect] for more details.

#### Example

```js
const detect = await call.detectDigit();
await detect.stop();
```

***

## **Events**

### onStarted

* **CallDetect.listen**(`{ onStarted: Callback }}`)

Emitted when the detecting session has started. Your event handler will be called with an instance of [`CallDetect`][calldetect].

#### Parameters

<ParamField path="detect" type="CallDetect" required>
  The detecting session that has started. See [`CallDetect`][calldetect].
</ParamField>

### onUpdated

* **CallDetect.listen**(`{ onUpdated: Callback }}`)

Emitted when the detecting session has been updated. Your event handler will be called with an instance of [`CallDetect`][calldetect].

#### Parameters

<ParamField path="detect" type="CallDetect" required>
  The detecting session that has updated. See [`CallDetect`][calldetect].
</ParamField>

### onEnded

* **CallDetect.listen**(`{ onEnded: Callback }}`)

Emitted when the detecting session has ended. Your event handler will be called with an instance of [`CallDetect`][calldetect].

#### Parameters

<ParamField path="detect" type="CallDetect" required>
  The detecting session that has ended. See [`CallDetect`][calldetect].
</ParamField>