# Answering machine detection: five AI checks on every bot call

The voice bot recognizes answering machines, voicemail and virtual receptionists, usually in a fraction of a second, and hangs up instead of talking to them.

Section: AI voice bot · Updated: 2026-11-03 · http://my.lptracker.ru/land/lk/faq/?a=answering-machine-detection&lang=en

> **In short:** Answering machine detection protects the voice bot from talking to machines: five independent AI checks listen to the answer and hang up if an answering machine, voicemail or a virtual receptionist picks up. By our data, it filters out 97% of answering machines, and the lead moves to the “Answering machine” step with a callback in 3 hours.

Answering machine detection decides what you pay for on outbound calls: conversations with clients or with machines. When you call a database, some calls inevitably reach voicemail, carrier answering machines and virtual receptionists. An ordinary robot politely talks to them: minutes and tokens are charged, and fake “conversations” show up in the CRM.

We see answering machine detection as our breakthrough. Every voice bot call is checked by five independent AI checks, and by our data the system filters out 97% of answering machines — in normal mode within a fraction of a second. The protection is on for every bot by default, so there is nothing extra to set up.

An answering machine is any machine that answers instead of a person: voicemail, a carrier recording saying the subscriber cannot answer, a company's phone menu or a virtual receptionist asking what to pass on.

## Why your business needs answering machine detection

- **Saves minutes and tokens.** The bot does not hold a conversation with a machine and does not waste reply generation — this shows on large calling campaigns.
- **A clean CRM.** The lead does not get a “Refusal” or a fake call summary: it moves to the “Answering machine” step, and the bot calls back later, when a person may answer.
- **Honest statistics.** In “Number statistics”, calls to answering machines are counted separately from answered ones, so you see the real connect rate for every number and client carrier.
- **Managers' time.** Nobody listens to recordings of the bot talking to machines or calls back an “interested” answering machine.

## How does answering machine detection work: five AI checks

The sound of the answer goes to the checks after every line from the other side. The checks run in the background and do not delay the conversation. They are arranged as a cascade: the first check that confidently recognizes a machine hangs up, and each check has its own confidence threshold so that live people are not dropped.

1. Recognizes a recording it has heard before. A carrier's answering machine plays the same prerecorded message, and the system recognizes it by its audio “fingerprint”.
2. Detects a synthesized or recorded voice. A neural network tells live speech from a voice generated by a machine or played from a recording, and it keeps learning from specialists' labels.
3. Voice biometrics. The system recognizes a voice that has already answered calls, whatever phrase it says.
4. Comparing the sound with a sample library. Short fragments of the answer are compared with a library of labeled answering machine recordings.
5. AI analysis of the conversation's meaning. The AI reads the course of the conversation and ends a call that is clearly going nowhere.

For looped answering machines that talk without pauses, there is a separate early check: it fires 15 seconds after the bot's line. In one call, such a machine was caught at the 18th second instead of the 194th. In normal mode a decision takes a fraction of a second, at peak hours up to a few seconds, but the conversation does not stop meanwhile.

## Specialists review calls every working day

Automation is good as long as it keeps learning. Every working day our specialists listen to calls where the protection fired and mark who answered: a machine or a person. New recordings go straight into the fingerprint, voice and sample libraries, and the checks pick them up without a restart. Since the end of July, more than 16,000 calls have been reviewed this way.

Carriers update their answering machines from time to time, changing phrases and voices. That is why the libraries are topped up constantly, and the synthesized voice detector is retrained from time to time on all the labels collected so far and tested on a held-out sample. The system starts recognizing a carrier's new answering machine as soon as specialists have reviewed it.

## What happens when the bot detects an answering machine

- The bot hangs up right away — the conversation with the machine does not go on.
- In “Call details”, the call gets the “Antibot” status, and the reason icon shows “Answering machine” (recognized by sound) or “Answering machine (by branch)” (by trigger phrases).
- The lead moves to the “Answering machine” step, and by default the bot calls back in 3 hours — when a live person may answer.
- In “Number statistics” in the “Phone numbers” section, these calls go to a separate “Voicemail” column and are not counted as answered: you see the share of answering machines for each number and client carrier.

The bot's call recordings are also kept in “Call details” — how to find and listen to them is covered in “[Sales call recordings](http://my.lptracker.ru/land/lk/faq/?a=call-details&format=md&lang=en)”.

![Answering machine detection: calls to answering machines with the “Antibot” status](http://my.lptracker.ru/land/n/multic/faq_media.php?f=2026-11/answering-machine-detection-1-en-cfa153.webp)

## How to set up answering machine detection step by step

The protection works out of the box, but you can tune it for your database. Everything is on the bot card: “Settings” → “General” → “Speech recognition settings” and the “Triggers” tab.

1. **Keep “Detect an answering machine in the first seconds of the call” checked** — It is on by default. Uncheck it only if calls drop in the first seconds: this happens when the number plays its own announcement before connecting, for example Avito proxy numbers.
2. **Extend the “Answering machine” trigger** — On the “Triggers” tab, open “Answering machine”, type a phrase and press Enter, or paste a whole list. The factory list has 564 phrases of answering machines and voice assistants.
3. **Add “Spam phrases”** — Phrases a machine repeats in a loop. The call ends when a phrase is heard the set number of times: “How many spam-phrase repeats end the call” is 5 by default, and 0 turns the check off.
4. **Check the hang-up on silence** — “Hang up if the customer stays silent in the first answer” is 14,000 ms by default, that is, 14 seconds. It cuts off answering machines that pick up and stay silent.
5. **Limit the call length** — “Number of characters in the dialog after which the call must end” (100,000 by default), “Maximum recognition time of the customer's first answer (sec)” (60) and “Maximum length of the whole call (sec)” (600). If the bot does get into a talk with a machine, the call will not eat your budget.
6. **Save** — Click “Save” in the bottom panel and check the end reasons in “Call details” after the first calls.

![The “Answering machine” trigger adds key phrases to answering machine detection](http://my.lptracker.ru/land/n/multic/faq_media.php?f=2026-11/answering-machine-detection-2-en-78f282.webp)

## Virtual receptionists and voicemail

Carriers' virtual receptionists sound lively and even ask questions like “What should I pass on?”. They are caught by the same synthesized voice and biometrics checks, and the factory list of the “Answering machine” trigger includes phrases such as “virtual receptionist”, “I am a virtual assistant”, “what should I pass on”, “voicemail” and “after the beep”.

If a receptionist still got through as a person, listen to the recording and add its phrase to the “Answering machine” trigger. The factory list is set when the trigger is created, so bots created long ago may lack the newer phrases. Other voice bot triggers — for example, [AI voice bot call transfer](http://my.lptracker.ru/land/lk/faq/?a=voice-bot-triggers&format=md&lang=en) — are set up on the same tab.

Was a person taken for an answering machine? Check the reason in “Call details”. “Answering machine (by branch)” means a phrase fired: remove it from the trigger or from “Spam phrases”. If the reason is “Answering machine” by sound, send the call clid to support — [how to send a sample call to support](http://my.lptracker.ru/land/lk/faq/?a=voice-bot-troubleshooting&format=md&lang=en) is covered separately.

## How much does answering machine detection cost

The cost of the check shows as a separate “Answering machine detection” line in “AI conversion analysis”, so you see what the protection cost in each campaign. The benefit is in the minutes and tokens of conversations the bot did not have with machines, and in leads that were not lost with a false result.

Money for calls that still reached an answering machine is not refunded. To get fewer of them, keep the checkbox on, add phrases of new answering machines, refresh the numbers in the carousel and call following the strategy from “[AI outbound calling bot](http://my.lptracker.ru/land/lk/faq/?a=voice-bot-outbound&format=md&lang=en)”.

## Frequently asked questions

### How does a voice bot detect an answering machine?
Five independent AI checks listen to the answer: they recognize a recording heard before, a synthesized or familiar voice, compare the sound with a sample library and assess the meaning of the conversation. The first check that confidently recognizes a machine hangs up.

### How many answering machines does the system filter out?
By our data, 97%. The rest are covered by the “Answering machine” trigger, “Spam phrases”, the hang-up on silence and call length limits.

### Why did the bot talk to an answering machine?
Most likely the carrier updated its recording or a new virtual receptionist answered. Add its phrase to the “Answering machine” trigger and send the call clid to support.

### What if the bot hung up on a live person?
Listen to the recording in “Call details” and check the reason. For “Answering machine (by branch)”, remove the phrase that fired from the trigger or “Spam phrases”; for “Answering machine” by sound, send the clid to support.

### Can I turn off answering machine detection?
Yes, uncheck “Detect an answering machine in the first seconds of the call”. Do it only if calls drop in the first seconds because of the number's announcement, for example an Avito proxy number.

### Do I get a refund for calls to answering machines?
No, these charges are not refunded. The protection shortens conversations with machines, and fresh numbers and added answering machine phrases reduce the rest of such calls.

**Read also:** [AI voice bot call transfer](http://my.lptracker.ru/land/lk/faq/?a=voice-bot-triggers&format=md&lang=en), [AI outbound calling bot](http://my.lptracker.ru/land/lk/faq/?a=voice-bot-outbound&format=md&lang=en), [AI voice bot troubleshooting](http://my.lptracker.ru/land/lk/faq/?a=voice-bot-troubleshooting&format=md&lang=en)