How to read the SIP Event Report and spot false answers

Sometimes the dialer thinks a call was answered when it really only rang. Agents get connected to dead air, your drop numbers look wrong, and the carrier swears nothing is amiss. The SIP Event Report is the tool built for exactly this problem — finding false answers by looking at the raw signalling, not the call status.

First: it only works if logging is on

This report is only useful if you have SIP Event Logging enabled on your system. That setting lives in the Campaigns area. Until it is on, the report has nothing to show, because it reads the stored SIP (Session Initiation Protocol) messages for each call. Turn it on, let some calls run, then come back.

What false answer supervision is

Answer supervision is the signal a carrier sends to say "this call was answered." When a carrier sends that signal during ringing — before a human actually picked up — that is false answer supervision. Your dialer believes it has a Live answer, routes the call to an agent, and the agent hears ringing or silence. It inflates costs and ruins your numbers because you are paying for and connecting calls nobody answered.

Sorting by ring-time

The report lets you sort the SIP messages for calls by several criteria. The trick is the Ring-Time column. Sort it up and down:

• Sort Ring-Time ascending and look at the calls that were "answered" almost instantly. A real human cannot answer in well under a second, so a cluster of near-zero ring times that the system counted as answered is your false-answer fingerprint.
• Sort descending to see the long-ringing calls and confirm normal behaviour for contrast.

flowchart TD
  A[Enable SIP Event Logging] --> B[Run calls, open SIP Event Report]
  B --> C[Sort Ring-Time ascending]
  C --> D{Answered with near-zero ring?}
  D -->|Yes| E[False answer supervision]
  D -->|No| F[Answers look legitimate]
  E --> G[Raise with carrier with evidence]

Each row ties back to a single call by its Asterisk uniqueid, so once you find a suspect you can follow the same call through your other logs and build a complete picture for the Carrier. Keep the full message sequence for a handful of those calls — the order of the signalling messages and their timestamps is the part a carrier cannot wave away, because it is their own equipment that sent the answer signal.

One more reading habit pays off here: do not judge a single call. False answer supervision shows up as a pattern, a cluster of near-instant "answers" that share a route or a destination prefix. A lone fast answer can be a real person who happened to be holding the phone. A hundred of them in a tidy band, all routed the same way, is a Carrier problem you can name precisely.

Where to go next

Confirm the suspect calls against the Dial Log Report — a 200 response paired with a one-second duration is the same story from a different angle. The Carrier Log Report gives you the downloadable proof to attach to a ticket. Start from the troubleshooting playbook when you are not sure which report fits the symptom.

On a VICIfast managed box, SIP event tooling is already wired up and your dialer is live in under 40 seconds. See plans and pricing.