VICIdial NOAUDIODATA-Hangup: Drop Silent Dead Calls Fast

Not every answered call carries a voice, or even a sound. Some calls connect and then deliver pure silence: a line that opened but never produced audio data. When answering machine detection (AMD (answering machine detection)) is running on your campaign, those calls still flow into the routing script and can sit there doing nothing useful. The NOAUDIODATA-Hangup option exists to kill them immediately, before they waste a channel or land on an agent.

What NOAUDIODATA-Hangup does

When a call goes through Asterisk AMD on your campaign, the result reaches an AMD routing script that decides where the call goes next. Most calls arrive with audio the detector can analyze. A few arrive with no audio data at all, usually because the carrier signaled an answer (Answer supervision) but no real media ever flowed. NOAUDIODATA-Hangup tells the routing script to drop those calls the moment they show up empty, instead of trying to classify them or pushing them to an agent.

This matters because a silent call that reaches an agent looks exactly like a real connection until the agent says hello three times and gets nothing back. That is lost talk time and a confusing Disposition. Dropping the call at the script keeps it out of the agent queue entirely.

Where the setting lives

NOAUDIODATA-Hangup is not a top-level campaign dropdown. It is a special option you enable inside the settings container behind the AMD Agent Route Options setting. Turn Agent Route Options on, open its container, and add the line NOAUDIODATA-Hangup-ENABLED. The same container is where you can add FAX-Hangup-ENABLED and FAS-Hangup-ENABLED to drop fax tones (Fax detection) and fax-answer-signal calls the same way. The container also holds your status-response pairs, one per line, separated by a comma.

Because the option is keyed to Asterisk AMD, it goes hand in hand with the AMD Type being set to the built-in AMD application rather than a third-party engine. For the wider mechanism around statuses and responses, see AMD Agent Route Options.

How a silent call gets dropped

flowchart TD
  A[Call answered] --> B[AMD runs]
  B --> C[Reach AMD routing script]
  C --> D{Any audio data}
  D -->|No audio| E[NOAUDIODATA-Hangup drops call]
  D -->|Has audio| F{AMD status}
  F -->|Human or Notsure| G[Send to agent]
  F -->|Machine| H[Hang up or play message]

When to turn it on

Enable NOAUDIODATA-Hangup when your AMD Log Report shows a steady share of calls with no audio reaching the script, or when agents complain about dead silent connections. It is most useful on high-volume predictive (Predictive dialing) and ratio (Ratio dialing) campaigns where even a small percentage of silent calls adds up to real wasted capacity across the day.

One caution: a true human can occasionally answer and stay quiet for a beat. The no-audio-data case is narrower than that, since it means the script received nothing at all, not just a slow hello. Still, if you run lossy carrier routes, watch your live-answer (Live answer) numbers after enabling it to confirm you are not clipping real people. The hangup cause (Hangup cause) logged on these calls also helps you tell carrier-side silence from genuine dead air.

For the full picture of how AMD and CPD fit together, read our AMD and CPD complete guide, and compare the hang-up path with the message path in hang up vs leave a message.

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