skip to Main Content

Toward A Community Developed IP Phone

A few days ago on the Asterisk Users Mailing List Tzafrir Cohen of Xorcom fame started an interesting thread about the possibility of a community developed IP Phone.

A common wisdom here is that one should use a proper hardware phone rather that an extra software on the user’s PC. Why is that such a big issue?

One thing that bothers me with the current crop of hardware SIP phones is that they are hopelessly proprietary.

So what would it take to build a fully-adaptable phone?

I am 100% behind the assertion that most users want a hard phone on their desk. Soft phones, even good ones, seem to be exclusively the domain of those who travel and vertical niches like call centers.

The thread goes on to consider various platform options as well as the existing work of Australia’s David Rowe. David seems like a most amazing guy, having taken an open source approach to telephony hardware to create a low cost embedded Asterisk platform, the IP04 based upon the Blackfin DSP.

Some think that using a common x86 CPU would make such a device easier for developers to handle. I’m not so certain that it matters all that much. I suspect that many functions inside an IP phone are better suited to DSPs than general purpose CPUs. But if the CPU is both cheap enough an sufficiently powerful such differences may be academic.

It seems that the development of hardware is more difficult on a community basis. But perhaps it’s not truly required? There are a number of hard phones available that already run an embedded Linux OS. Perhaps these are platforms just waiting to be exploited?


For precident let us consider the venerable Cisco/Linksys WRT-54GL. While fundamentally sold as a consumer router, ready-to-roll out of the box, the GL variant is often paired with third party firmware like DD-WRT, OpenWRT, Sveasoft or Tomato.

When Cisco decided to migrate away from Linux as the basis for the device there was such a public outcry that they reinstated the Linux based product along side the new WxWorks based model. I wonder just how many WRT-54GL they have sold at a small premium just to support this third party developer markeplace? There are in fact over 20 different firmware releases developed around the WRT-54G series.

snom_820_links_hoch_perspektive_200pxTurning our attention to existing IP phones the name that leaps out at me is snom. They are well known to have Linux based products, and also produce high-quality hardware. If suitable documentation was available then perhaps there’s a hardware basis for beginning a project.

Beyond snom there are of course a number of low-cost phones available  from various Asian manufacturers. However, it’s difficult to see how sucessful the project could be if it relied upon sub-standard hardware. If the proponents aim to compete with the likes of Polycom, Nortel, Cisco & Avaya then the look and feel of the hardware simply must be top-shelf.

zultys_zip_4x5We can look to the past and see an example of Linux based phones that didn’t quite make the cut in the Zultys 4X4 and 4×5 models. A few years back I was very interested the the potential of the Zultys 4×5 for my home office as well and a friends travel agency business. I bought a 4×5 very early in their availability and did some basic interoperability testing with Asterisk.

This phone had so much going for it. Here’s the basic overview:

  • Linux based
  • Built-in router with 4 port switch with QoS management
  • Web-based admin interface
  • POE powered
  • 1 FXO for lifeline support
  • Built-in calculator functions
  • Wired headset jack (2.5mm)
  • Bluetooth
  • VPN end-point functionality
  • Supported SRTP

The theory was that you could drop one of these into someones home, connect it to their DSL or cable modem and make it the core of a home office network. In my friends case it would VPN connect to the travel agencies main office and route all calls securely back to their PBX.

The problem was that the physical hardware was a little flaky. The buttons didn’t have a good feel. The handset was too light and plasticky. Also many functions had slightly awkward keypress sequences. Finally, the POTS line could not be redirected at the PBX for the purpose of VM. These are the sort of things that can cripple a potentially great device.

Ultimately it was Zultys themselves who forced me to set the device aside as unusable. At the time they refused to deal with end-users for firmware issues, instead directing me to their reseller. But their resellers were completely unable to provide support in depth. If the device had been community supported perhaps that would not have been the case.


Or perhaps such a project would go totally another direction. It seems that OpenPeak has some extremely nice hardware. They are supposed to be opening up widget development to third parties, and even offering to sell widgets from their web site.

That people are expressing frustration with existing IP phones is clear indication of an opportunity. There’s a chance for someone to introduce the desk phone reimagined from a brand new perspective.

This Post Has 7 Comments
  1. Way back when, I did a post that DIgium needs to create a standard for an open source (Android?) phone. Since they have the base and evidently no interest in making phones, and would be the primary beneficiary of cheaper IP phones, it seems like a no brainer.

    Creating a decent phone based on today’s model’s would not be hard. The opportunity that lies in such a direction is improved management, improved control, and improved feature sets on the phone. For example: Asterisk phones are very difficult to configure from Asterisk. The microbrowser’s are very model and brand specific and are unable to get any real traction – Digium could fix this.

    I can’t figure out what Digium is thinking by either ignoring phones are pushing Polycom. When we sell a proprietary phone system – about 50% of the retail price goes to the manufactuter. When we sell a Digium phone system (Switchvox) about 10% of the retail price goes to Digium (and these systems are about the same price). Considering the popularity of SIP trunks, I would assume the Asterisk hardware market is getting smaller. You would think they would be all over the phones, but if they are it is a well kept secret.

  2. This struck a chord with me. As we are developers of an open source sip stack, we’re always looking for IP phone platforms that we can develop on.

    So far no luck, I mean we can get our hands on some development boards such as for ARM (and it runs fine), but it’s a long way from there to an IP phone.

    Or maybe jump start it via OpenMoko as a sort of wireless IP Phone?

    In any case, we would be ready to contribute the SIP stack to such open source IP Phone.

  3. I love the OpenPeak stuff, thats my vision of a phone, big touch screen, no buttons, the ability to do anything and everything.

    It just needs to be open so it can do what we want not what they think we want …

  4. Well there’s the Neo Freerunner (and OpenMoko project), an open hardware mobile phone with all the features you’d expect from a modern mobile (GSM, Bluetooth, WiFi, GPS). Stick that in a larger box, add any other required interfaces (LAN, DECT) though the provided SD or USB interfaces, and you’d surely be in business!

    Then there’s all the Linux gum-stick-type expandable SBC’s out there. Lots of ready made starting points, I’d have thought.

    1. Perhaps, but that project seems perilously close to its end. There’s been a of of bad news from them lately.

      Besides, mobile phones are definitely specialty items. There’s a lot of optimization around the air interface that would add cost and not be applicable to a desk/home phone. I still think that a higher end snom would a nice hardware platform as the basis of such a project.

  5. True enough. Do you know anything about the spec of the Snom phone you refer to? CPU/DSP/etc – that type of stuff? I’ve always wondered what goes into a “serious” VoIP phone.

    And speaking of Snoms, do you still plan to sell your M3 system? If so, please email me ASAP on the supplied address! :o)

  6. PS – oops, my textual smiley seems to have been transmogrified into something else!

Comments are closed.

Back To Top
%d bloggers like this: