Tag Archives: asterisk

Personal VOIP/PBX using Asterisk, part 2

This is part two of my series on how to set up an asterisk server for home use on a Linode VPS — but is applicable to any host that doesn’t have additional hardware telephony devices installed in the server. Please refer to Part 1 for how to set up the dummy timing module.

Also, before continuing, please read my little sidebar post about IP telephony codecs. Most specifically the part on adding iLBC codec to the asterisk config. Then “read more” below for the rest of this post.

Continue reading Personal VOIP/PBX using Asterisk, part 2

IP Telephony Codecs

My first stumbling block when installing and trying to get Asterisk PBX working were the codecs and mismatching. If both ends of a connection can’t negotiate the same codec, the call won’t complete.

I grabbed the recommended asterisk config for gizmo5 and when attempting to place a call to my gizmo call-in number which should have landed it into my PBX I got the following errors and it disconnected:

[Jan 14 01:40:20] WARNING[23334] channel.c: Unable to find a codec translation path from 0x400 (ilbc) to 0x4 (ulaw)
[Jan 14 01:40:21] WARNING[23334] channel.c: Unable to find a codec translation path from 0x400 (ilbc) to 0x2 (gsm)

When trying to determine what went wrong, I found that ilbc is no longer part of Asterisk config, and ulaw is actually G.711 using the  µ-law algorithm. I also found that one can add iLBC codec to Asterisk by agreeing to a license agreement and running a script.

So hence this blog post, so I can document what I’ve learned and hopefully prevent someone else from having same frustrations.

Continue reading IP Telephony Codecs

Personal VOIP/PBX using Asterisk, part 1

Background

Voice over IP is simply placing phone calls over the Internet instead of  traditional phone lines. This means the calls are usually cheaper, but not free in many cases since often the telco lines have to get involved at some point to either originate or terminate a call. However, true voip calls are almost always free, no matter where in the world they are.

There are many commercial products out there already that makes this easy for a user, like Vonage and Comcast’s voice, but they have fairly hefty monthly fees. They do usually offer unlimited domestic (U.S.) calls.   But they also have drawbacks, like, ah not working if the power or cable goes out.

The next few posts will document my experience in rolling my own voip service.

Part 1 is compiling the support drivers on my “Linode” for Asterisk.

Click through for the details…

Continue reading Personal VOIP/PBX using Asterisk, part 1