IPPBX

IP-PBX (Internet Protocol Private Branch Exchange) is a private telephone switching system that uses an IP network to route calls both within an organization and to external networks. Unlike traditional analog or digital PBX systems, IP-PBX relies on packet-switched networks and SIP-based signaling to connect endpoints such as IP phones, softphones, and unified communications applications.

Core components include the IP-PBX server, SIP endpoints, VoIP gateways to connect to PSTN networks, voicemail and auto-attendant, call routing scripts, call queues, conferencing, and presence features. It can be deployed on-premises as an appliance or virtual machine, or delivered as a hosted or cloud service. It integrates with SIP trunks and UC applications, providing mobility and integration with CRM, collaboration tools, and messaging.

Typical features include extension dialing, voicemail, call forwarding, IVR, auto-attendant, call recording, conferencing, call analytics, fax over IP, security features such as encryption and access control lists, and quality of service management. It supports scalability by adding endpoints and lines without significant hardware reconfiguration.

Considerations for IP-PBX include network reliability, bandwidth, latency, and jitter; quality of service management; security against eavesdropping and tampering; and regulatory compliance for call recording and emergency services. Standards: SIP is the predominant signaling protocol; H.323 is older but still present in some environments. IP-PBX is a central component of many unified communications and cloud-based communications strategies.