Gone are the days when Telephony companies could dream of selling customers a large PBX that can be loaded only with their proprietary modules. This fantasy of Corporate Telephony companies (save a few) has been shattered due to the advent of one strong open source telephony/communications platform – Asterisk, and one strong communications protocol – SIP.

What is Asterisk?

While it is easy to think of Asterisk as an open source IP PBX/VOIP Server for both small and large companies that runs on commodity hardware, their website says that Asterisk is much more than that – An Engine that powers PBX & Many Communications Applications.

“Asterisk is to communications applications what Apache web server is to web applications.”

Can We Use Asterisk as an IP PBX/IP Telephony Server?

Of course. You can install Asterisk in your Linux/Unix-based system using the package manager in your OS. Or, you can install the Linux-based Asterisk distribution ‘Asterisk Now’, that provides an (optional) graphical user interface for installation and maintenance of Asterisk, using FreePBX. And yes, it’s free of cost. See here for more info on Installation.

An enterprise-grade telephony server is now a few clicks away!

What else do we need to run Asterisk?

  1. A Server or a Computer (for small installations) to host Asterisk, preferably stand-alone and connected to the Network.
  2. Analog or Digital Interface Cards to connect Analog/Digital Trunks and Analog/Digital phones to the Server. These cards are inserted into the PCI/PCI-Express slots of the server. Digium, the company behind Asterisk development, or other telephony interface card manufacturers like Sangoma, sell these cards. BTW, Digium also offers Switchvox (a commercial IP PBX) and SIP Phones. This is how the creator of Asterisk makes money.
  3. An existing Local Area Network (LAN) to carry all communication signals around the office – Network Switches, Network Cables, etc.
  4. SIP Phones – SIP is the open-standard for communications. A SIP phone from any vendor should work with Asterisk. If the phone has two switch ports built-in, one port can connect to the network switch and the other port can connect to the computer – at each desk. Compare that to connecting IP phone & Computer using two separate cables from the network switch.

What else can we do with Asterisk?

The most popular application of Asterisk is to use it as an IP Telephony Server/VOIP Switch/IP PBX, to send/receive phone calls in SMB/Enterprise companies. In addition to this, Asterisk can also be used for other applications like,

Conference Bridge for Existing PBX/Asterisk:

While a simple 3-way conference bridge is built into most business PBX systems, multi-party conference units are often sold as an additional component costing a lot of $$$. A system running Asterisk conferencing module could be integrated with an existing PBX (over IP, mostly) and can provide multi-party conference services for a small additional cost.

VOIP Gateway:

If a Traditional PBX can’t connect directly to IP Trunk lines (like SIP Trunks over the Internet), Asterisk can act as a gateway between Traditional PBX & SIP Trunks. When Asterisk is used as a VOIP Gateway, it can, through Digium Cards, integrate with Traditional PBX using analog/trunk ports and enable analog/digital phone users to dial out/receive calls using SIP Trunks.

Call Center Functionality:

Call Centers require specific telephony functionality like Call Queue distribution, Customized Integrated Voice Response (IVR), Dialers, Call recording, Live Monitoring, Centralized Reporting and others. Asterisk can be customized to provide these solutions or Asterisk-based systems can be used for the same.

The bottom-line is: Whether your company has 10 employees or 10,000 employees, Asterisk can provide reliable, customizable & feature rich telephony services at a relatively low-cost. There are many businesses based on Asterisk (products, support, etc.) and it’s an excellent example of how open source solutions have scaled up to match/exceed the levels of commercial vendors.