Professional Telephone System

Would You Like A Professional Telephone System For Your Office Or Home For Free?
By Mike Furlong

Skeptic or not, I can anticipate some of the questions that you're thinking.

"What's the catch?"

Well the software really can be downloaded and used for free. It's called Asterisk. It's available under the GNU Public License. It has developed its own following and even has an annual convention. Commercial systems have also been developed around Asterisk.

Asterisk was originally developed by Mark Spencer, who works at a company called Digium. But many others have now contributed to Asterisk. That's the beauty of open-source software. Running Asterisk gives you the capabilities of a private branch exchange (PBX). Some of the features include voicemailboxes, call forwarding, call screening, call blocking, automatic call distribution (ACD), music-on-hold, complete incoming and outgoing call-logging and reporting, wake-up calls, and interactive voice response (IVR). You know IVR right? The dreaded press 1 if you're impatient ... over and over. It allows you to attach telephones that can call each other extension to extension. Each extension is private and the calls you make from one to another are private. You can hold, transfer, and make conference calls with ease.

"What does Asterisk run on?"

It runs on a PC. The operating system it runs under can be Linux (its first and probably preferred system), or some other flavor of Unix, or even Windows now I believe. But before you ask. Linux is also available free under the GNU Public License. And many people run Asterisk and Linux on an old cast off PC that they bought for $50 on eBay (at least for small systems). Although like any program, the bigger and snappier your PC is, the better it runs. And the more users your system can support.

"How do I make calls from one extension to another?"

You can run a software program on a PC that communicates with the server and functions like an extension on a PBX. The communications between your PC and Asterisk use industry standard Voice Over Internet Protocols (VoIP). Actually there are different protocols available. You can configure which one Asterisk will use for most of the available devices it can communicate with. Session Initial Protocol (SIP) is a widely-used and popular one. You need a PC with a sound card. And you need either microphone and speakers. Or instead of speakers you can use a headset. Most of these programs put a picture of a phone on the screen and you click on the buttons to dial. If there is another PC on your network running a similar program, you call it just like you would on a real PBX. The program digitizes your voice and sends it over your computer network using VoIP.