Environment
- Independent PBX per site with different vendors and firmware levels
- Duplicate extension ranges across offices
- Handsets configured individually with default administrative credentials in places
- No central call reporting
Distributed services business
Multi-site VoIP consolidation
Several offices each ran their own phone system with separate providers and inconsistent numbering. Internal calls went out over the PSTN, and no one had a full picture of the numbering or of who could dial internationally.
- FreePBX
- Asterisk
- Grandstream
- SIP trunking
Architecture
- Central FreePBX platform with per-site outbound routes and local breakout where required
- Unified extension plan and DID-to-destination map documented per number range
- Site-to-site connectivity over VPN for inter-office dialling
- Zero-touch provisioning templates per handset model
- Outbound classes for internal, national and international calling
Implementation
- Numbering and IVR logic documented from each legacy system before any change
- Pilot site migrated first with the legacy PBX kept ready for rollback
- Handsets re-provisioned from templates, default credentials removed
- TLS signalling and SRTP media enabled and verified on live channels
- Remaining sites cut over in sequence with a validation checklist per site
Outcome
- Inter-office calls now stay on-net rather than traversing the PSTN
- One consistent dial plan, IVR structure and reporting view across all sites
- Handset replacement is a provisioning swap rather than a manual rebuild
- International dialling is granted by class, not available to every extension by default
Scope the work before you commit budget
Send the environment details and get an engineered proposal with assumptions, risks and a rollback path.