Playing With Asterisk

Asterisk is the Open Source PBX software that can manage telephone lines. As well as the classical hardware phones, more importantly for me, it also manages VOIP traffic. I decided to give it a go after I received our last quarterly telephone bill and discovered that we had spent £110 talking to my daughter in the period.

An initial trial last week managed to allow my daughter to call in from outside and have a voice conversation with me (who was inside the house). This is with two firewalls (one at her place and one at mine) in the path. Unfortunately, there was a problem with my microphone.

Over the weekend I extended that further, connecting the Free World Dialup and used there echo service to take a call and bounce it back to me.

I have also ordered a linksys SPA3102 so that I can try and connect a real phone into the process.

I was worried that yet another application running on my server would bog it down, but it doesn’t appear to be a problem with CPU load rising from an average of around 2% to about 5% when asterisk is bridging a call including changing codecs (and therefore presumable de-encoding and then re-encoding the voice on the channel).

I still have a problem with sound quality but it seens to get better with every tweak that I do. Lets hope over the next week I can get it working fully.