April 16, 2005

Asterisk at Home

Being rather a long way from home, it's fairly important to stay in touch with friends and family from back in Australia. Generally for me this has been limited to email and the occasional phone call, but phoning tends to get rather expensive after a while, and those back home are somewhat reluctant to call because of the high cost involved.

I have looked at various options for this, such as cheap long distance providers and netmeeting/Skype things, but they are all quite limited in some way or another, as well as not making it easy for other people calling me.

In comes Asterisk and VoIP to the rescue. Asterisk is a complete open source PABX software suite developed mainly for Linux. It has the full featureset of a full PABX (multiple extensions, voicemail, call redirection, conference calling, etc) but with the added bonus of having full voice-over-ip support.

The real kicker on this is the last point. There are now lots of companies around the world who will offer you connections over the internet into the public phone network, so that wherever you are in the world, you can make and take calls to and from normal phone lines using a computer or internet phone. Of particular note is that you can link up to many of these services with an Asterisk PABX.

Over the last couple of weeks, I have been playing a lot with this, and have setup a connection with an Australian VoIP provider. This means now that I have a Sydney local call phone number which when called goes over the net to my home Asterisk server, and from there I take the call. And of course it works the other way around - if I dial Australia from home, Asterisk routes the call over the net to the provider where it pops out of the PSTN. And at 14cents flat rate for a local call, it cant be beaten! I'm currently evaluating a few providers to get cheap calls for Snow to Thailand and Asterisk will also automagically route those calls.

Even better...I have multiple phones attached to my Asterisk server. One is a Cisco 7960G - which is a VoIP phone in a regular handset but with lots of funky features. I've also got some softphones running on my desktop and laptop computers.
I can thus take and make calls from all of these 'phones'. And given that the phones dont have to be in the same place as the Asterisk server, I can also run the softphone on my laptop at work. The softphone at work simply routes the connection over the internet to my Asterisk box at home. So any calls can also be made and received at work! This is nothing short of amazing, and has impressed plenty of people. :)

The next step is to hook my local Dutch PSTN line into the Asterisk server. This then allows Asterisk to handle all calls to and from my .nl phone. And to top this, I could even have calls from Australia redirect to my mobile phone wherever I am by having Asterisk call out over this PSTN line if the other phones dont answer.

But wait! There's more! By using this PSTN connection, I can dial in from my dutch mobile, then call through to Australia. Or I can call in and have Asterisk read me my email, tell me the temperature at home, or just read my my voicemail.

It seems that there is no end to the possibilities with Asterisk - the more I play, the more I discover so I think I'll be twiddling with it for a long time yet.

Posted by Ben at April 16, 2005 12:21 AM
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