What does the tag silence in calls report mean?

Question

When is a call leg tagged with silence? What does the tag silence in calls report mean?

Answer

The tag silence indicates periods when no audio is detected on a call leg. The presence of the silence tag can indicate a technical problem with the call, but is also applied in some situations that don't indicate a problem.

The phone provider used by Zendesk applies this tag under specific technical conditions related to the audio stream between the caller and the system.

Scenarios

• No audio packets received: If the system stops receiving audio packets, referred as RTP, from one side of the call, the call leg receives the tag silence, even if the interruption is only temporary.
• Silent audio packets received: If the system continues to receive audio packets, but the packets contain no actual audio, the call leg receives the tag silence. For example:
  • If a call is an automated notification or reminder, the recipient may simply listen without a response, which results in the tag silence.
  • If a caller mutes their phone, based on their device or phone system, this may send silent audio packets or stop sending audio entirely. These situations can trigger the tag silence.

Note: Some phone systems generate comfort noise instead of silence, which may inhibit the application of the tag silence.

How to use the tag silence

Do not use the tag silence on its own to determine call quality or identify problematic calls. It is most effective when combined with other data points, such as high_jitter, high_packet_loss, high_pdd, or high_latency, and user feedback to help identify possible audio issues.

Example

A customer receives an automated reminder call, they listen but don't speak. The call leg may receive the tag silence even though the call functioned as expected.

For more information, see this article: Reporting on network and audio quality for voice.