Our Blog

We can't shut up.

You are here: Home Our Blog Our new open-source phone system
May 25 2010

Our new open-source phone system

In May 2010, we installed a long-overdue new phone system here at Groundwire HQ. It's pretty awesome, and since one of our superpowers is showing how the technology sausage is made, we're pleased to share with you the geeky details and hope that you're inspired by the possibilities.
Our new open-source phone system

Our new phones are even smart enough to be branded correctly

In May 2010, we installed a long-overdue new phone system here at Groundwire HQ. It's pretty awesome, and since one of our superpowers is showing how the technology sausage is made, we're pleased to share with you the geeky details and hope that you're inspired by the possibilities.

Until recently, we had a typically horrible nonprofit phone system: a mid-90s AT&T/Lucent "Partner Plus." It was mostly cobbled together out of used parts. It had decent phone handsets, but that was about all that was nice about it. Extensions would occasionally die or spontaneously get a bad case of static interference. Adding new phones was almost incomprehensible. It couldn't forward a call outside of the office (say to someone's cell phone) and we couldn't put extensions in our field offices. Worst of all, we had grown to the point where we were up against the maximum capacity of the system.

Fortunately for all of us, phone systems have come a long way in the past 15 years. We were intrigued by the promise of modern VoIP (Voice Over IP) phone systems that offer flexibility, point-and-click administration, and cheap, standards-based commodity hardware. We were also looking to gain a few specific capabilities that our old Partner Plus couldn't dream of:

  • Easy configuration of new phone extensions
  • The ability to put phones in our field offices that would be seamlessly connected to our main system
  • Voicemail that could be delivered as email attachments
  • Low-cost phone handsets with a choice of manufacturers
  • A flexible, easy-to-configure auto-attendant/voicemail system
  • A solid dial-by-name directory
  • An in-house conference bridge

And of course, we wanted it to be cheap.

We wound up implementing a phone system powered by commodity PC hardware, standards-based phone handsets and open-source software.  Here come the nerdy bits, so skip down to "Results" if your eyes glaze over.

The Nerdy Bits

The beating heart of our phone system is Trixbox CE software, which wraps up several powerful open-source telephony modules (most notably, Asterisk and FreePBX) an a basic install of CentOS Linux into a single, easy-to-use small office phone system.   And because it's open-source, the price is right: zero.

The system is running on a Dell PowerEdge 1950 server, which we bought used for about $1400.  It's got dual power supplies and mirrored hard drives, and was a solid entry-level server when it came out in 2007, but isn't otherwise all that powerful.  

We wanted to stick with "traditional" phone lines provided by our current phone/internet vendor.  We already had our phone lines coming in on our T1 connection from  Integra Telecom.  That's been rock-solid and we wanted to keep it, so Integra switched us to a PRI connection, which we connected into our new phone server via a Sangoma A101 T1 PRI card ($800).  We sprang for the hardware echo cancellation option to ensure maximum sound quality.

We chose Cisco 7960 IP phones, which are a widely used and popular phone handset.  We picked them up used off of eBay for about $130 a pop. If we had to do it again, we'd choose the slightly newer Cisco 7961G, which has support for standard power-over-ethernet, which lets the phones get power from your Ethernet network wiring if you put in an appropriate switch.  We wound up having to buy power adapters for the phones instead (at about $15 each), because it turned out that these phones were built before the power-over-ethernet standard was finalized, and as a result, they can only get power from expensive Cisco switches.  Bummer.

Open source is not just free as in beer and as in speech; it's free as in kittens. Nerdy though we are, we didn't want to install of a mission-critical business system using unfamiliar software all alone. We hired Cascadeo to do the initial phone system configuration and to show us how to manage it from there. Total consulting cost was about $5000.  We saved a significant amount by having Cascadeo configure the server and the first 6-7 phones, and then Groundwire Office Manager Sean Pender and I configured the rest of our ~25 handsets.  It was a bit tedious and a bit geeky, but fairly simple.

With some help from former Groundwire tech director Dean Ericksen, we're now in the process of configuring SonicWall VPN routers in our field offices, so they can have a permanent, secure network connection back to Seattle. Field office phones will run over this connection, and it also provides field staff with access to our fileserver. This means you can simply dial the main Groundwire number to reach any of our staffers (not quite yet, but soon!) no matter which office they're in.


We've been up and running for about three weeks now, and things have been a breeze. Our staff love their new phones. Sean and I love the ability to manage everything through a web-based interface. 

Our total cost for the entire system with 25 phones was about $12,000 including all of the hardware, software and consulting help. We probably invested another 20-30 hours of our own time to configure and tweak everything to our satisfaction. You'd probably wind up spending a bit less of your own time and a bit more consulting expense.


We've have never gotten through this (or even gotten started) alone. A big Groundwire shout-out to:

  • The funders who provided financial support for the equipment needed for our phone system: The Norman Archibald Charitable Foundation and the Norcross Wildlife Foundation
  • Dean Ericksen of Ericksen Inititiatives for VPN configuration, purchasing advice and general wisdom. 
  • Chris Ellis and the team at Cascadeo for their Trixbox configuration wizardry.
  • Steve Albertson and the crew at Community Voicemail for the loaner switch.
  • Richard Amerman, for getting us pointed in the right direction and guiding us through a proof-of-concept deployment.
Very glad the system is working for Groundwire. If some of the gotchas and idiosyncrasies can get worked out, there are a lot of small offices that would love to trade $12K for a phone system of this kind.
Probably Asterisk is the best when it comes to open-source phone system software. Hands down!
Loved the article. I currently work on an Avaya phone network but got the green light to begin looking into replacing it with an open source solution. This article was a great start for me.

Add Yours…

You can add a comment by filling out the form below. Plain text formatting. Comments are moderated.