PBX and IP-telephony platforms – the systems that run an organisation’s phone service: SIP call routing, extensions, IVR/auto-attendant, voicemail, call queues/centre features, and trunking to carriers.
This category covers the PBX platforms, distributions, and SIP servers themselves – Asterisk- and FreeSWITCH-based distros (FusionPBX, Issabel, Wazo, VitalPBX), pure SIP servers (Kamailio, OpenSIPS), and commercial appliances/systems (Grandstream UCM, Yeastar, Sangoma Switchvox). The core engines (Asterisk, FreeSWITCH) and the meeting/UC clients and hosted-voice suites (3CX, RingCentral, 8x8, Zoom, Webex) are evaluated under Unified Communications.
What a PBX Platform Covers
Mix (10 tools)
License: 6 open source · 4 proprietary
Hosting: 7 self-hosted · 0 SaaS · 3 both
Call routing (SIP) – registrars, dial plans, and inbound/outbound routing across extensions and carrier trunks (SIP/PRI).
Telephony features – IVR/auto-attendant, voicemail, ring groups, call queues, recording, and conferencing.
Trunking & interop – SIP trunk providers, codecs, NAT traversal, and session border control.
Management – web admin for extensions, devices (provisioning), and reporting; multi-tenancy for MSPs.
Deployment – on-premises (bare metal / VM), turnkey appliance, or a vendor-hosted cloud PBX.
The field splits into open-source platforms built on Asterisk or FreeSWITCH, standalone SIP servers for large-scale routing, and commercial appliances or hosted systems. Open-source options dominate self-hosting; commercial offerings lead on turnkey hardware and support.
About this data & disclaimer
The information on these pages was researched by a combination of human review and large language models. This catalogue serves as a reference for the resources, applications, devices, deployment payloads, and other components that the ResorsIT platform integrates, deploys, and manages. To suggest an addition or correction, please contact us. Prepared by Rhodium Systems Inc., author of the ResorsIT platform — a unified IT operations management platform for IT teams and MSPs that integrates a curated suite of open-source, commercial, and SaaS applications into a single system with shared identity, single sign-on, access control, and a common audit trail. This information is compiled on a best-effort basis: it may be incomplete, contain errors, and become out of date as tools, vendors, licences, and features change. Use this catalogue only as a starting point for your own research, and independently verify and review any tool carefully against your own requirements before relying on it.
Comparison
Cross-tool comparison of PBX platforms, distributions, and SIP servers.
Overview Comparison
| Tool | Type | Engine | License | Deployment |
|---|---|---|---|---|
| FusionPBX | PBX platform | FreeSWITCH | MPL-1.1 | Self-hosted |
| Issabel | PBX distribution | Asterisk | GPL-2.0 | Self-hosted / appliance |
| VitalPBX | PBX platform | Asterisk | Proprietary (free tier) | Self-hosted / appliance / cloud |
| Wazo Platform | Programmable UC | Asterisk | GPL-3.0 | Self-hosted |
| Kamailio | SIP server | native SIP | GPL-2.0 | Self-hosted |
| OpenSIPS | SIP server / SBC | native SIP | GPL-3.0 | Self-hosted |
| Grandstream UCM | IP PBX appliance | Asterisk | Proprietary | Appliance |
| Yeastar P-Series | PBX system | proprietary | Proprietary | Appliance / software / cloud |
| Sangoma Switchvox | IP PBX / UC | Asterisk | Proprietary | Appliance / cloud |
| sipXcom | UC system | native SIP | LGPL-2.1 | Self-hosted |
Capabilities
| Tool | Multi-tenant | Call Centre / Queues | Provisioning UI | Best For |
|---|---|---|---|---|
| FusionPBX | Yes | Yes | Yes | MSPs hosting many tenants on FreeSWITCH |
| Issabel | Limited | Yes | Yes | All-in-one Asterisk PBX with a console |
| VitalPBX | Yes | Yes (add-on) | Yes | Commercially-backed Asterisk PBX |
| Wazo Platform | Yes | Via API | Yes | Developers/operators building on an API |
| Kamailio | N/A | N/A | No (config) | Carrier-scale SIP routing / registrars |
| OpenSIPS | N/A | N/A | No (config) | SIP load balancing and session border control |
| Grandstream UCM | No | Yes | Yes | Turnkey SMB hardware PBX |
| Yeastar P-Series | No | Yes | Yes | SMB with appliance + Microsoft 365 integration |
| Sangoma Switchvox | No | Yes | Yes | Turnkey commercial PBX with support |
| sipXcom | Limited | Basic | Yes | Native-SIP UC without an Asterisk core |
Suitability Summary
- Best OSS multi-tenant (MSP): FusionPBX (FreeSWITCH) or Wazo Platform.
- Best OSS all-in-one PBX: Issabel; VitalPBX where commercial backing is wanted.
- Best SIP infrastructure at scale: Kamailio (routing/registrar) and OpenSIPS (load balancing / SBC).
- Best turnkey appliance: Grandstream UCM, Yeastar P-Series, or Sangoma Switchvox for organisations that want vendor hardware and support.
For the core telephony engines (Asterisk, FreeSWITCH) and hosted-voice and meeting suites, see the Unified Communications category.
Tools
13 tools.
Asterisk
Asterisk is the foundational open-source telephony framework, originally created by Mark Spencer at Digium (now Sangoma Technologies).
License: GPL-2.0-only (OSS) · Kind: web · Deploy: docker · SSO: none
ResorsIT usage: Web App without SSO
Access & Identity: Forward-auth · Vaulted credential
Evaluated under Unified Communications.
FreePBX
FreePBX is a widely deployed open-source PBX management framework built on Asterisk, providing a web GUI and modular system for extensions, IVR, queues, call recording, and SIP trunk management.
License: GPL-3.0-only (OSS) · Kind: web · Deploy: docker · SSO: none
ResorsIT usage: Web App without SSO
Access & Identity: Forward-auth · Directory / LDAP
Evaluated under Unified Communications.
FreeSWITCH
FreeSWITCH is a scalable open-source telephony platform designed from the ground up as a general-purpose communications engine, not just a PBX.
License: MPL-2.0 (OSS) · Kind: web · Deploy: docker · SSO: none
ResorsIT usage: Web App without SSO
Access & Identity: Forward-auth · Vaulted credential
Evaluated under Unified Communications.
FusionPBX
FusionPBX is an open-source, multi-tenant web GUI and management platform built on the FreeSWITCH engine for running a full-featured VoIP PBX.
License: MPL-1.1 (OSS) · Kind: web · Deploy: direct, docker · SSO: none
ResorsIT usage: Web App without SSO
Access & Identity: Forward-auth · Vaulted credential
Grandstream UCM
Grandstream UCM is a line of on-premises IP PBX appliances providing voice, video, conferencing, and unified communications for small and medium businesses.
License: Proprietary (proprietary) · Kind: hybrid · Deploy: appliance · SSO: none
ResorsIT usage: Web App without SSO
Access & Identity: Forward-auth · Vaulted credential · Key-based access
Issabel
Issabel is an open-source unified communications distribution built around Asterisk, bundling a PBX, email, fax, and collaboration tools with a web console.
License: GPL-2.0-only (OSS) · Kind: web · Deploy: direct, appliance · SSO: none
ResorsIT usage: Web App without SSO
Access & Identity: Forward-auth · Vaulted credential · Key-based access
Kamailio
Kamailio is a high-performance open-source SIP server (proxy, registrar, router) used to build large-scale VoIP, presence, and real-time communication infrastructure.
License: GPL-2.0-only (OSS) · Kind: service · Deploy: direct, docker · SSO: none
ResorsIT usage: Deployment Payload
Access & Identity: Vaulted credential · Local host account · Key-based access
OpenSIPS
OpenSIPS is an open-source SIP server and session border controller for routing, load balancing, and managing high-volume VoIP and real-time communications traffic.
License: GPL-3.0-only (OSS) · Kind: service · Deploy: direct, docker · SSO: none
ResorsIT usage: Deployment Payload
Access & Identity: Vaulted credential · Local host account · Key-based access
Sangoma Switchvox
Sangoma Switchvox is a commercial Asterisk-based IP PBX and unified communications system offered as an on-premises appliance or a hosted cloud service.
License: Proprietary (proprietary) · Kind: hybrid · Deploy: appliance, direct, saas · SSO: none
ResorsIT usage: Web App without SSO
Access & Identity: Forward-auth · Vaulted credential · Key-based access
sipXcom
sipXcom is an open-source unified communications system built on a native SIP architecture, providing PBX telephony, presence, and conferencing with a web admin UI.
License: LGPL-2.1-only (OSS) · Kind: web · Deploy: direct · SSO: none
ResorsIT usage: Web App without SSO
Access & Identity: Forward-auth · Directory / LDAP
VitalPBX
VitalPBX is a commercial Asterisk-based PBX platform (with a free community edition) offering a web GUI, multi-tenancy, call centre features, and add-on modules.
License: Proprietary (proprietary) · Kind: web · Deploy: direct, appliance, saas · SSO: none
ResorsIT usage: Web App without SSO
Access & Identity: Forward-auth · Vaulted credential · Key-based access
Wazo Platform
Wazo Platform is an open-source, API-driven programmable telephony and unified communications stack built on Asterisk, aimed at operators and integrators.
License: GPL-3.0-only (OSS) · Kind: web · Deploy: direct, docker · SSO: none
ResorsIT usage: Web App without SSO
Access & Identity: Forward-auth · Vaulted credential
Yeastar P-Series
Yeastar P-Series is a commercial PBX system available as an appliance, software, or cloud service, with call centre, UC, and Microsoft 365/LDAP integrations.
License: Proprietary (proprietary) · Kind: hybrid · Deploy: appliance, direct, saas · SSO: none
ResorsIT usage: Web App without SSO
Access & Identity: Forward-auth · Directory / LDAP · Key-based access
