Wednesday, October 6, 2010

VOIP up and running

It's been a big afternoon, where do I start?

My asterisk config isn't perfect yet, but I've got users set up at least. My first choice of VOIP company wanted to play silly buggers by charging me more and then asking me how much extra they had charged as a security measure, but wouldn't accept a value in New Zealand dollars, and wanted a 30 day turn-around before letting me call my own country, so I figured I'd let it slide and try somewhere else. I ended up signing up with, eventually got the worst of the config set up (made more amusing by the config being modularised, reminded me of trying to configure freeradius and apache after they changed their config structure), with some basic outgoing extensions, and managed to get calls going through to my cellphone.

I had two main problems though:
  1. The sound was really jittery
  2. I could hear from my cellphone to my softphone but not vice-versa
 It turns out these were both related, but we'll get back to that in a second.

The next fun part was configuring my N95 to register with my server. I found a ton of guides, the simplest one being here. My phone wanted to register as a user, so one of these had to be set up too (best tute here), and then everything was all hunky dory. But then I came across the fun part - when I called my home number from my cellphone, the connection was fine, but no sound was going through either way! I had a look at my asterisk output, and it was complaining about conversion paths between ulaw and g729. Turns out you need a license to use it, or at least the codec, and I had neither. However, removing g729 from my config and letting it default to ulaw not only made the sound work, but killed the jitter I was getting!

The only thing stopping me using this now for cheap calls (apart from the lag from going to america and back) is how much of a pain it is to get Asterisk to handle a plus sign at the start of the extension. Otherwise, I'm really happy with this setup for now.

[quick edit] Got it parsing + signs now (thanks), but it turns out the sound doesn't work with calls to cellphones, only landlines... I'll have another look tomorrow.

No comments:

Post a Comment