> Fetch clean Markdown by appending `.md` to any page URL under https://signalwire.com/docs or requesting it with the HTTP header `Accept: text/markdown`. The root index at https://signalwire.com/docs/llms.txt lists the available documentation indexes. # detect_machine > Detect whether the other end of the call is a machine (fax, voicemail, etc.) or a human, using AMD and fax detection. [variables]: #variables [statuscallbacks]: #statuscallbacks A detection method that combines AMD (Answering Machine Detection) and fax detection. Detect whether the user on the other end of the call is a `machine` (fax, voicemail, etc.) or a `human`. The detection event(s) will be sent to the specified `status_url` as a POST request, and the current detection state or final result will also be saved in the `detect_result` [variable][variables]. ## **Properties** **`detect_machine`** `object` — required An object that accepts the following properties. --- **`detect_machine.detect_message_end`** `boolean` — default: false If `true`, stops detection on beep / end of voicemail greeting. --- **`detect_machine.detectors`** `string` — default: amd,fax Comma-separated string of detectors to enable. **Valid Values:** `amd`, `fax` --- **`detect_machine.end_silence_timeout`** `number` — default: 1.0 How long to wait for voice activity to finish (in seconds). --- **`detect_machine.initial_timeout`** `number` — default: 4.5 How long to wait for initial voice activity before giving up (in seconds). --- **`detect_machine.machine_ready_timeout`** `number` — default: value of the end\_silence\_timeout parameter How long to wait for voice activity to finish before firing the READY event (in seconds). --- **`detect_machine.machine_voice_threshold`** `number` — default: 1.25 The number of seconds of ongoing voice activity required to classify as MACHINE. --- **`detect_machine.machine_words_threshold`** `integer` — default: 6 The minimum number of words that must be detected in a single utterance before classifying the call as MACHINE. --- **`detect_machine.status_url`** `string` The HTTP(S) URL to deliver detector events to. Learn more about [status callbacks][statuscallbacks]. --- **`detect_machine.timeout`** `number` — default: 30.0 The maximum time to run the detector (in seconds). --- **`detect_machine.tone`** `string` — default: CED The tone to detect. Only the remote side tone will be received. (`CED` or `CNG`) Used for fax detection. --- **`detect_machine.wait`** `boolean` — default: true If `false`, the detector will run asynchronously and `status_url` must be set. If `true`, the detector will wait for detection to complete before moving to the next SWML instruction. --- ## **Variables** The following variables are available after the `detect_machine` method is executed and detection is complete. You can reference these variables in your SWML script utilizing the `${variable}` syntax. **`detect_result`** `machine | human | fax | unknown | detecting | error` The lowercase SWML variable value for the current detection state or final result. Callback lifecycle events such as `READY`, `NOT_READY`, and `finished` are never assigned to this variable. --- **`detect_machine_beep`** `true | false` Whether a beep was detected. `true` if detected. --- **`detect_ms`** `integer` The number of milliseconds the detection took. --- ## **StatusCallbacks** > **Status callbacks are advisory** > > Status callbacks are asynchronous, best-effort HTTP notifications: delivery can be delayed or fail silently — if your server is unreachable, the callback simply never arrives. Don't gate time-critical or business-critical actions solely on receiving one. Confirm state via the REST API before acting, or use a transport with visible failure modes — see [Status callback reliability](/docs/platform/webhooks#status-callback-reliability). A POST request will be sent to `status_url` with a JSON payload like the following: **`event_type`** `string` The type of event, always `calling.call.detect` for this method. --- **`event_channel`** `string` The channel for the event, includes the SWML session ID. --- **`timestamp`** `number` Unix timestamp (float) when the event was generated. --- **`project_id`** `string` The project ID associated with the call. --- **`space_id`** `string` The Space ID associated with the call. --- **`params`** `object` An object containing detection-specific parameters. --- **`params.control_id`** `string` The control ID for this detect operation. --- **`params.detect`** `object` Detection result details (see subfields below). --- **`detect.type`** `string` The type of detection. **Valid values:** `machine` or `fax`. --- **`detect.params.event`** `string` The detector event value in the status callback payload. Detection outcome values are `HUMAN`, `MACHINE`, and `UNKNOWN`. Lifecycle marker values are `READY`, `NOT_READY`, and `finished`. `READY`, `NOT_READY`, and `finished` only appear in callback payloads and are not valid `${detect_result}` values. The lowercase `finished` value is intentional. --- **`detect.params.beep`** `boolean` Present and set to `true` when a beep was detected. Absent when no beep has been detected. --- **`params.call_id`** `string` The call ID. --- **`params.node_id`** `string` The node handling the call. --- **`params.segment_id`** `string` The segment ID for this part of the call. --- ### Raw JSON example ```json { "event_type": "calling.call.detect", "event_channel": "swml:be38xxxx-8xxx-4xxxx-9fxx-bxxxxxxxxx", "timestamp": 1745332535.668522, "project_id": "xxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx", "space_id": "xxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx", "params": { "control_id": "xxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx", "detect": { "type": "machine", "params": { "event": "MACHINE", "beep": true } }, "call_id": "xxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx", "node_id": "xxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx", "segment_id": "xxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" } } ``` --- ## **Examples** ### Play the detection result #### YAML ```yaml version: 1.0.0 sections: main: - detect_machine: status_url: 'https://example.com/detect-events' timeout: 20 - play: url: 'say:Detection result: ${detect_result}' ``` #### JSON ```json { "version": "1.0.0", "sections": { "main": [ { "detect_machine": { "status_url": "https://example.com/detect-events", "timeout": 20 } }, { "play": { "url": "say:Detection result: ${detect_result}" } } ] } } ``` ### Conditional actions based on the detection result #### YAML ```yaml version: 1.0.0 sections: main: - play: url: "say: Welcome to the machine detection test." - detect_machine: status_url: "https://webhook.site/5c8abf82-b8c7-41c8-b5d6-b32a40068109" detectors: "amd,fax" wait: true - cond: - when: detect_result == 'machine' then: - play: url: "say: You are a machine, goodbye." - hangup: {} - when: detect_result == 'human' then: - play: url: "say: You are a human, hello." - hangup: {} - when: detect_result == 'fax' then: - play: url: "say: You are a fax, goodbye." - hangup: {} - else: - play: url: "say: Unable to determine if you are a human, machine, or fax, goodbye. Result was ${detect_result}" - hangup: {} ``` #### JSON ```json { "version": "1.0.0", "sections": { "main": [ { "play": { "url": "say: Welcome to the machine detection test." } }, { "detect_machine": { "status_url": "https://webhook.site/5c8abf82-b8c7-41c8-b5d6-b32a40068109", "detectors": "amd,fax", "wait": true } }, { "cond": [ { "when": "detect_result == 'machine'", "then": [ {"play": {"url": "say: You are a machine, goodbye."}}, {"hangup": {}} ] }, { "when": "detect_result == 'human'", "then": [ {"play": {"url": "say: You are a human, hello."}}, {"hangup": {}} ] }, { "when": "detect_result == 'fax'", "then": [ {"play": {"url": "say: You are a fax, goodbye."}}, {"hangup": {}} ] }, { "else": [ {"play": {"url": "say: Unable to determine if you are a human, machine, or fax, goodbye. Result was ${detect_result}"}}, {"hangup": {}} ] } ] } ] } } ```