On a previous entry I spoke about Trixbox and how you can turn it into a weapon to protect yourself against unwanted calls (see: Trixbox can help stop those annoying calls). Though Trixbox excels at disrupting incoming calls from telemarketers on dedicated equipment, it also works decently well in a shared environment.

As my cell phone is all I need for making calls these days, I don’t have a standard telephone connection in my apartment. Regardless, it can be nice to have the functionality of Trixbox so I currently have it installed on a Windows XP box that acts both as a casual gaming computer and a Trixbox PBX using Microsoft Virtual PC 2007.

Usability

If you have no need to keep your PBX server running 24 hours a day, a shared computer is a cost effective way to go. While the hardware you’re running it on and amount of free memory can provided mixed results for the response time to your commands on the web-based interface and playback of built in audio files/voicemails, the actual call quality is just like any other installation - crystal clear.

To actually handle my calls. I have an Aastra 480i CT and a few cordless handsets. This phone is a great multi-line device with a full screen that can pull up custom designed web pages (once used to remotely control my iTunes software). I had no issues with getting this device to talk to the virtual installation of Trixbox, as Virtual PC 2007 acts like it’s just another computer out on the network by having a unique IP address that is not affected at all by the host computer’s firewall. The 480i CT also excels at plug and play in a Trixbox environment — I just had to tell Trixbox to assign the phone’s MAC address to a specific phone extension. After that I just plugged the phone in, waited a minute for it to boot up, and watched as it gathered the configuration data from the server.

So a question in my mind as I write this is: Would a software based phone provide the same amount of quality? I can’t see why not. As long as computer resources don’t put an intense amount of strain on both the host computer and the virtual PBX server, it should be fine. Or you can pick up a cheap GS-101 if you don’t need a fancy phone, but prefer using a handset over a computer microphone.

Connections

When I had a full PBX server, I had a FXO card so I could interface with the standard POTS (phone company) line and a VoIP link so I could get to the outside world when the POTS line was in use. In my current setup I just have a VoIP link.

Could the FXO card work in a virtual server setup? I can’t really answer that since I don’t have the FXO card installed in the computer, but I tend to be thinking that it could not work. Virtual PC 2007 shares various types of hardware - keyboards, mice, audio cards, and display adapters…but it does it in a way that you have to use specific Virtual PC drivers to access some of that hardware to get the most use out of it.

Virtual PC 2007 comes with special drivers if you install a Windows based operating system inside of it that will improve the speed and functions of that virtual operating system. As Trixbox runs in Linux, we do not have the option to take advantage of those drivers. Thankfully Trixbox is aware enough to access the virtual network card and other basic essentials.

So until I have the chance to install the FXO card again, that will be a mystery…but not an issue. My VoIP link is all I will ever need for this system.

Right now I have VoIP service through a company called Vitelity Communications. While their initial startup cost is higher than many other providers, their call and telephone number rates are some of the best I’ve found. The initial cost (as of this post) that gets turned into an account credit is $35. You can also add an 800 number for around $0.50 a month.

Setting up Vitelity inside of Trixbox is the same as configuring any other VoIP service. You add a trunk (SIP or IAX) with the specific login information that your VoIP provider supplies you and route calls through that trunk.

Issues & Reliability

Now, as I mentioned earlier, there are issues with the output of voice prompts and voicemail messages. When you play back a voicemail or try to navigate through an IVR, the audio is playing back at about half the speed it should be. I recorded an example that you can listen to below:

Other issues, such as internet latency and issues with your host operating system, could also cause issues with your call quality and VoIP server performance. If you’re going to use a PBX server for full time use, I would recommend dedicated equipment and a FXO card to connect your system to the local POTS service.

Virtual PC 2007, while an excellent free application from Microsoft, is not without fault. While so far I haven’t run into any serious issues, I did notice that if I interact with the application (right click on its icon, for instance), the virtual operating system will stop processing any functions. This can cause some issues (such as with the system time), but hasn’t been something that I have had to worry about yet.

Summary

If you’re interested in testing the waters of VoIP and Trixbox, this is the cheapest way to do it. You’re not going to get the best setup and you may run into issues like I have spoken about above, but it could be a good starting point to see if you’re at all interested in building a dedicated box and routing your calls full time over Trixbox.

Also the best support you are going to get for your Trixbox installation is at the official forums. There are many highly skilled and certified Trixbox users there who know more about the system and how it works than I ever will.

If you have any questions or corrections to something I have mentioned in this piece, please leave a comment and let me know.