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FreePBX Level 3 – Advanced Engineering and Diagnostics

This course moves beyond FreePBX administration and into the lower-layer behaviour of the platform, with a focus on secure signalling, command-line tooling, custom dialplan integration, development-led telephony features and structured diagnostics under real operational pressure.

It is built for engineers who already understand FreePBX and now need to work confidently with fwconsole, the Asterisk CLI, generated and custom dialplans, secure SIP media flows, bespoke feature development, API-driven IVR behaviour, and advanced fault-finding for call flow, call quality and system loading.

FreePBX Frog

Course purpose

Develop the advanced engineering judgement needed to secure, extend and troubleshoot FreePBX and Asterisk systems below the GUI layer, especially where default module behaviour is not enough and reliable diagnosis matters more than trial-and-error changes.

Duration

  • 1 day for experienced FreePBX and Asterisk engineers
  • 2 days if you want deeper labs around dialplan development, APIs and diagnostics

Target audience

  • senior FreePBX administrators
  • telephony engineers and escalation staff
  • MSP engineers responsible for customisation and advanced support
  • Asterisk-capable administrators working with FreePBX estates
  • technical staff who need to build or diagnose bespoke telephony logic

Prerequisites

Ideally learners will have:

  • completion of FreePBX Level 2 or equivalent real-world experience
  • confidence with FreePBX modules, trunks, routes, queues and feature behaviour
  • working understanding of SIP and PJSIP concepts
  • basic Linux shell confidence and willingness to work below the GUI

This course assumes learners are already comfortable with operational FreePBX administration.

Learning outcomes

  • explain how SIPS and SRTP protect SIP signalling and RTP media paths
  • use fwconsole and the Asterisk CLI more confidently for inspection and control
  • read and reason about Asterisk dialplan behaviour below the FreePBX GUI
  • integrate custom dialplan logic with FreePBX more safely
  • understand the structure and purpose of a custom Superfecta module
  • design a custom IVR workflow using external APIs for voice-to-text and text-to-voice functions
  • diagnose complex issues involving call flow, media quality and platform load with more structure
  • make safer engineering decisions during advanced change, support and recovery work

Detailed module structure

Unit 1: Secure SIP with SIPS and SRTP

Topics:

  • what SIPS secures
  • what SRTP secures
  • signalling path vs media path
  • certificate and trust awareness at a practical level
  • common deployment expectations and failure modes
Security framing: encrypted signalling does not automatically guarantee correct media security unless the RTP side is also designed and verified properly.

Unit 2: Using fwconsole safely and effectively

Topics:

  • what fwconsole is for
  • common operational commands and where they fit
  • module, reload and service awareness
  • reading before changing
  • supportability and operational caution when working below the GUI

Unit 3: Asterisk command line and runtime inspection

Topics:

  • why the Asterisk CLI matters
  • core inspection concepts at runtime
  • reading channel, endpoint and call behaviour live
  • using CLI visibility to validate assumptions
  • avoiding unnecessary restarts while investigating issues

Unit 4: Asterisk dialplans and execution logic

Topics:

  • how dialplans are structured conceptually
  • contexts, extensions, priorities and applications
  • execution flow and branching awareness
  • reading dialplan behaviour instead of guessing
  • where FreePBX-generated logic sits in the larger picture
Core concept: advanced call-flow engineering becomes much easier once learners understand dialplan execution as a logical program rather than a PBX black box.

Unit 5: Integrating custom dialplans with FreePBX

Topics:

  • why custom dialplan logic is sometimes needed
  • working with FreePBX rather than fighting generated configuration
  • keeping custom logic maintainable and upgrade-aware
  • clear separation between supported and bespoke behaviour
  • testing and rollback thinking for custom integrations

Unit 6: Designing a custom Superfecta module

Topics:

  • what Superfecta does in a caller-information workflow
  • module structure awareness at a practical level
  • where custom data sources fit
  • maintainability, documentation and upgrade considerations
  • what makes a useful bespoke module vs an over-engineered one

Unit 7: Building a custom IVR dialplan with external APIs

Topics:

  • where custom IVR logic goes beyond standard GUI features
  • voice-to-text and text-to-voice service concepts
  • API request and response awareness in telephony workflows
  • latency, reliability and fallback considerations
  • why external dependency design matters in a live call path
Engineering message: once APIs sit in the call path, resilience, timeout handling and fallback behaviour become just as important as the feature itself.

Unit 8: Advanced call flow diagnostics

Topics:

  • tracing a call through modules, generated logic and dialplan steps
  • using the CLI and logs together
  • distinguishing route problems from dialplan problems
  • understanding where the call actually failed
  • capturing evidence before changing live behaviour

Unit 9: Diagnosing call quality problems

Topics:

  • what poor call quality can indicate
  • jitter, delay and packet-loss awareness
  • signalling success vs media failure
  • one-way audio and no-audio thinking
  • using structured evidence instead of assumptions

Unit 10: System loading and performance behaviour

Topics:

  • what loading means for a PBX platform
  • CPU, memory, disk and service pressure at a practical level
  • recognising overloaded behaviour in telephony symptoms
  • why media handling and external integrations can change resource expectations
  • capacity and scaling awareness

Unit 11: Safe customisation and change control

Topics:

  • documenting bespoke logic clearly
  • keeping custom code supportable across upgrades
  • backups and rollback before advanced changes
  • separating experiments from production telephony
  • building maintainable rather than fragile solutions

Unit 12: Advanced operational good practice

Topics:

  • testing custom logic in a structured way
  • preserving service stability during investigation
  • using logs, CLI output and metrics together
  • knowing when to simplify the design
  • making advanced systems supportable by the next engineer

Labs

  • review a secure SIP deployment and identify where signalling and media protection apply
  • use fwconsole and the Asterisk CLI to inspect a live or simulated service state
  • trace a call through generated and custom dialplan logic
  • design the structure of a custom Superfecta data source or module
  • map a custom IVR workflow using an external voice-to-text and text-to-voice API
  • diagnose a call-quality scenario using structured evidence
  • review a loading incident and explain the safest next operational action

Assessment

Advanced engineering exercise

  • identify the likely layer of failure in a complex telephony issue
  • explain where custom logic should or should not be introduced
  • outline a safe approach to integrating or testing bespoke dialplan behaviour
  • describe how to investigate call flow, call quality and loading without destabilising the PBX

Advanced knowledge check

Explain how you would secure, extend and troubleshoot an advanced FreePBX system using SIPS and SRTP, command-line tooling, dialplan understanding, custom module logic, API-driven IVR behaviour and structured Asterisk diagnostics.

Deeper FreePBX understanding - Better custom telephony design - Stronger advanced diagnostics

Built for engineers who need to secure, customise and recover complex FreePBX and Asterisk environments with confidence

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