My VoIP setup at home

Recently, I had to work from home a bit more. Email and IM is great for communicating with my colleagues and friends, but sometimes talking to them is much more effective. So I decided to finalize my VoIP setup.

Skype

Of course, Skype is the obvious choice for calling friends and relatives. It works great for voice and video on both Windows and my Ubuntu 9.04 (yes, I'm still on Jaunty). My webcam (a cheap Microsoft LifeCam VX-100) is not that well supported on Ubuntu, but it's not so bad. And I use a FreeTalk Everyman USB headset (I got it free at ITExpo in January, thanks to Dan York!).

But Skype itself is not the ultimate answer, at least not for me. Not all my colleagues use Skype at work. So why use Skype Out and pay for local calls when I already have a land line? And I don't like holding a (traditional) phone for one hour when I'm on a conference call with customers or other people at the office. I want to be able to put both of my hands on my laptop keyboard to take notes.

SIP at home



The answer to this is SIP, and three components:

• A VoIP adapter. Mine is a Linksys SPA 3102 ATA, a VoIP adapter and gateway from Cisco. This little box converts ordinary (land line) calls into VoIP (SIP) calls, and vice-versa.


• Asterisk, a free open-source software PBX. A PBX is the kind of system that can play messages to callers, ask for input, route calls, hold conference calls, queue calls, etc. PBXs are usually costly pieces of hardware that you don't want to buy just for you personal needs.


• A SIP softphone.

So my land line is connected directly to the VoIP gateway, which is itself connected to my wired network. When I receive a call on my land line, if I do not answer after a predetermined amount of time, the call is converted to a VoIP call and transferred to Asterisk on my Linux server. Asterisk tries to transfer the call to my SIP phone. If I ignore the call or when I'm not available, the call is simply sent to Asterisk's voice mail module, which will send me a notification email with the recorded message attached to it.

When I want to place a call, I simply enter the number on my softphone, press ENTER, et voilà!

Of course, this whole setup requires a bit of configuration and dialplan programming.

Receiving SIP calls

The only thing that I did not explain is how I can receive SIP calls from outside my home network. I sometimes need the ability to receive calls when I test outbound telephony applications on platforms like Tropo or Teleku.

In order to do this, I created an account on Ekiga.net, a free VoIP service provider. I then configured Asterisk to automatically register (login) to my Ekiga.net account and transfer all calls to my SIP phone when I'm available.

SIP phones

I mainly use two different SIP phones, depending on which OS I boot. On Windows, I use X-Lite free edition. It has a lot of features, has video, but it only supports one account. On Linux, I use Twinkle, which is also free. It does not support video, but it is more stable than the Ekiga softphone on my machine, supports two lines, and has some basic voicemail support.