EPABX Systems

Context

Electronic Private Automatic Branch Exchange (EPABX) systems form a core part of institutional telecommunication, enabling automated internal and external call routing. Their evolution from electromechanical to digital and VoIP-based technologies has significantly improved efficiency and integration with modern communication networks

What is EPABX?

EPABX stands for Electronic Private Automatic Branch Exchange.
It is a private telephone switching system that facilitates internal communication within an organization and interfaces with external phone networks via the Public Switched Telephone Network (PSTN).
It allows for call routing, forwarding, voicemail, interactive menus, and internal extensions without requiring a separate physical line for each phone.

Functional Components and Mechanisms:

Internal Communication: Call routed via extension numbers using internal switching without accessing the PSTN.
External Communication: Requires dialing an access code (commonly '0'), following which EPABX routes the call to a trunk line connected to the PSTN.
Incoming Call Handling:
- Manual routing via a receptionist (in legacy systems).
- Automated Call Routing and IVRS (in modern systems).
Switching Mechanism:
- Older models used electromechanical relays and crossbar switches.
- Newer systems use digital switching with Pulse Code Modulation (PCM) and Time Division Multiplexing (TDM).
- Latest systems support Voice over Internet Protocol (VoIP) with IP-based switching, call recording, voicemail, and real-time routing.