I have recently been working on RaspberryPi GNU sipwitch servers. I actually have two things in mind for this. The first is a simple and complete stand-alone secure free software voip “switch” anyone could deploy and use, much like a FreedomBox for VoIP, as a kind of wallwort with ethernet you can plug into any router. A low cost and general purpose secure VoIP server does I think have appeal, and producing complete pre-configured and assembled servers would certainly be more interesting than selling project t-shirts. The second idea is a sipwitch VoIP public wifi access point to enable anonymous secure calling, like pictured here.
The RaspberryPi itself shown here was actually won in the recent Fedora participant open hardware giveaway contest. While I do participate in Fedora as a packager, in recent years I tended to focus more on Debian, and currently do have the Debian derived RaspberryPi distro on it. I would be happy to try Fedora for arm on it as well, especially since I do package sipwitch for Fedora.
I also maintain an active package archive in GNU Telephony that now includes both armel and armhf packages for Debian Wheezy, as well as mipsel for use with entirely free hardware and bios, such as the Lemote yeeloong netbooks. This archive can be added to any Debian related distro adding “deb http://www.gnutelephony.org/archive/ wheezy/” to a sources.list. I also have squeeze packages, and I include both source and binary packages for everything I build. Awhile ago I found a simple means to automate production of multiple binary architectures through the use of qemu as part of my normal release process for those packages I maintain. Having a publicly accessible Debian archive updated for each new release seemed a natural extension of this.
The sipwitch coventry voip and wifi access points really came about because I originally wanted a sipwitch raspberrypi server I could take with to conferences to setup and demo, complete with an entirely portable communication infrastructure that I could use. Too often I have been at conferences where infrastructure was not available in the presentation rooms, or otherwise not suitable for this, like what happened to me several years ago at Harvard, which had password restricted wifi and isolated individual machines from each other. It also fits well into GNU Telephony’s goal of developing self-organizing mesh networks and community grids.
In respect to presentations with this initial experimental access point, it could be rather interesting to be able to accept VoIP calls for q&a from the local audience directly. It would be even more interesting if we can get a network to tie to for the ethernet side that would allow remote voice and video participation as well. I want to re-think how such presentations are done, and how to make it easier for remote participation in general. These all offer interesting ways to demonstrate and promote the freedom of free software to think, imagine, and go beyond how things are done today.
The specific use of a powered usb hub was to avoid the problem with too little power on the RaspberryPi to drive a wifi device. This is not needed when using it as a pure voip wall-wort through local ethernet, and that would likely be the most convenient and widespread form factor I would propose building, and of course that has some natural overlap with the FreedomBox effort. Another interesting idea that came out of this effort was to create a RaspberryPi hylafax server using usb fax modems.
The particular choice of coventry itself as a name for our RaspberryPi VoIP servers really came from the idea of what to properly call a collection of bruja de sip del GNU servers, which, spectacularly obviously, would have to be some form of coven.