The Debugging section of your Telnyx portal account will contain several tools you will use for the purpose of debugging SIP calls and call control flows.

The Debugging section can be found on the left-hand list of portal modules nested within the Reporting header. Once you have entered the Debugging section there will be 4 headers, Sip Call Flow Tool, Prog. Voice Call Flow Tool, Detail Record Search and Webhook Deliveries.

Using the Sip call flow tool is straightforward. You can specify a date range that extends back 3 days maximum, and the calling and/or destination numbers.
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Additional filters include:

More info on SIP response codes can found here.

Below is a screenshot of an example call flow found using the Call Flow Tool.

The Programmatic Voice Call Flow Tool is much simpler, and can be used to view Call Control, TeXML or Fax API flows provided you can supply the Call Session ID of the call in question.

By clicking on the example that appears once you hit Search, you can open up the Call Inspector which illustrates the flow of the call. Below is a screenshot of an example flow found using the Prog. Voice Call Flow Tool. There is also a clickable drop-down beside each call event that will open up it's associated webhook.

The Web Dialer is a powerful debugging tool that will allow you to make test calls without needing to setup a softphone or PBX system. This is useful if you are having issues with calls and want to eliminate your PBX or softphone client as a potential source of the issue. In order to use the web dialer, you simply need a Credentials Connection, a DID number assigned to that connection and then you can assign a Caller ID name value if you wish to test that also. Once these pre-requisites are met you can make test calls straight from the web interface.

You can also receive incoming calls from the Web dialer – this is useful for testing inbound failures.
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To receive an inbound call, simply dial the DID number assigned to the SIP Connection that you have entered in the steps above.

If you come across this websocket response, make sure to check out the specific call rejection within the message. You can see a list of error responses and their resolutions here.

This tool shows a history of webhooks sent over a customers account. You can either search by webhook delivery id, or filter according to time, status and webhook name (eg. “call.initiated”).

You can use this tool to assist with debugging cases:

The Message content, and metadata is also included in the webhook delivery tool:

This feature provides customers with a visual representation of the Quality of Service (QoS) of any given call on a timeline with two separate graphics, one for each of the RTP media streams that are established for each call.

The new report feature is available in the Mission Control Portal through the SIP Call Flow Tool. Simply search for your call, click the blue "Call Data Debugging" button to the right of the sample and click the "QoS" tab. Reports are based on RTCP reports that are sent between SIP devices and Telnyx.

See picture for reference:

When a call is established media starts flowing over two RTP streams, one in each direction. Periodically, each side also sends RTCP reports to report transmission and reception statistics during the interval. Each report includes the number of packets sent (packets), the accumulated packets that were expected but never received (packets_lost), the jitter perceived from the received packets (ia_jitter), and more.

The QoS report feature uses the data on these RTCP reports to display 4 different quality metrics on a timeline for each RTP stream. Let’s take a look at what these metrics mean, and how it is displayed in the report: