FreePBX

Learn how to optimize call center operations in **FreePBX** by configuring agent penalty rules and time-based escalation workflows. This guide covers assigning agent penalty tiers, constructing dynamic escalation rules via `queuerules.conf`, and setting up robust failover strategies to manage call spikes while maintaining Service Level Agreements (SLAs).

This guide demonstrates how to configure compliant E911 emergency outbound routes and caller ID overrides in FreePBX. You will learn how the FreePBX Caller ID hierarchy operates during emergency calls, how to assign location-specific emergency CIDs to extensions, and how to set up internal emergency notifications. Implementing these configurations ensures compliance with **Kari's Law** and the **RAY BAUM'S Act**.

Learn how to use the **FreePBX Dynamic Routes** module to execute live SQL queries against external databases during call processing. This guide covers architecture, ODBC driver setup, SQL query design, and mapping database return values to custom PBX destinations. Implementing dynamic database lookups enables real-time decisions such as VIP routing, account status checks, and language preference matching.

Learn how to safely inject custom Asterisk dialplan logic into FreePBX without risking overwrites during GUI reloads. This guide covers the architectural mechanics of **extensions_custom.conf**, context hooking, and registering custom code with FreePBX **Custom Destinations**.

With **chan_sip** officially deprecated and removed in modern Asterisk releases, migrating FreePBX trunks to **chan_pjsip** is a critical maintenance task for administrators. This guide outlines the structural differences between legacy and modern channel drivers, provides mapping logic for trunk parameters, and details step-by-step procedures for transitioning both registration-based and IP-authenticated trunks. Readers will learn how to resolve port binding conflicts, configure PJSIP trunks cleanly in FreePBX, and execute seamless cutovers.

This guide details how **DRBD (Distributed Replicated Block Device)** powers block-level storage replication in **FreePBX High Availability** deployments. Readers will explore the architectural foundation of network-based RAID-1, synchronous replication protocols, and integration with cluster resource managers like Pacemaker and Corosync. Mastering DRBD mechanics ensures robust VoIP service failover, data integrity across database instances, and reliable state maintenance for critical telemetry.

Learn how to design, configure, and maintain an enterprise-grade **FreePBX High Availability (HA)** cluster using **Pacemaker**, **Corosync**, and **DRBD**. This guide covers active-passive failover architecture, shared storage replication, cluster constraints, STONITH fencing, and SIP endpoint persistence strategies to ensure maximum uptime for critical voice services.

Learn how to architect, configure, and maintain automated backup routines and offsite archiving for **FreePBX** deployment environments. This guide covers leveraging native module capabilities to separate configuration metadata from heavy media files like call recordings and voicemails. Implementing these offsite archival practices ensures fast **disaster recovery** and compliance with data retention policies.

Corosync provides the essential cluster membership and messaging infrastructure for **FreePBX High Availability (HA)** deployments. This guide covers how Corosync operates beneath Pacemaker to maintain quorum, manage node state, and prevent split-brain scenarios in voice environments. Readers will learn the core concepts, configuration mechanics, and monitoring commands needed to manage cluster messaging effectively.

Learn how **audio compression** works in VoIP and how codec selection impacts call quality, bandwidth consumption, and server performance in FreePBX. This guide explains the differences between narrowband, wideband, and adaptive codecs like **G.711**, **G.729**, **G.722**, and **Opus**. You will also learn how to configure codec priorities and minimize transcoding CPU overhead on your system.

Inbound SIP calls connect but only one party hears audio when the PBX sits behind a NAT router.