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.

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

Training scope and tailoring

The training plan shown above is provided as a structured guide to the typical scope and direction of the course. Our training content is reviewed and refined over time, so the precise balance of modules, examples and exercises may vary when the course is delivered.

Where there are specific topics, technologies or operational outcomes that are particularly important to your team, these can normally be incorporated into the delivery plan by prior agreement. Training is not treated as a rigid, fixed package; it is adapted where appropriate to reflect the client environment, delegate experience level, group size and the objectives agreed in advance.