Hi Denver, > I'm building some FOSS tools that let people send/receive calls/SMS without > a cell plan (mainly using VoIP carriers that also offer SMS/MMS). Eventually > I would like to be able to bundle these tools with a phone that runs only > free software.
A phone that runs only free software? What kind of phone would it be hardware-wise: do you plan on building your own hw, or are you trying to repurpose/reprogram some existing phone hw units? Not just to Denver but to everyone: please remember that with *ANY* libre or FOSS phone goal, the software is the easy part; the hard part is the hardware. > In order to still provide standard emergency calling features (112/999/911 > calling/SMS), the phone would require a free baseband (like FreeCalypso), but > it would not need to offer any non-emergency phone features, since those > would be handled by the aforementioned FOSS tools primarily on wifi. In terms of the required hardware, there is no difference between emergency-only and fully functional cellular capability. Even if all you seek to do on cellular networks is to have emergency call capability, you still need a GSM (or other cellular) antenna, RF tract (RF transceiver, power amplifier, antenna switch, SAW filters, impedance matching networks etc), GSM (or other cellular) baseband processing circuits like radio signal modulation and demodulation, speech codec and so forth. The FreeCalypso modem we are currently building is one example of the required set of hardware circuits; the various mainstream commercial implementations are alternative examples. The *only* hardware feature which can be omitted if you wish to limit cell functionality to emergency calls only is the SIM socket. The SIM socket I use on the FCDEV3B costs $2.12 in quantity 1 at Digi-Key (or down to $1.38 per piece when buying 1000-piece reels), and my opinion is that if you omit the SIM socket on your phone in order to *artificially* restrict its cellular capabilities to emergency calls only, you are being antisocial by artificially hobbling your product to suit your particular prejudices. Even if you do omit the SIM socket, you won't be able to remove all circuits for talking to the SIM as those circuits reside in the same silicon as other essential functionality - instead you will just artifically render those circuits non-functional by leaving the chipset's SIM interface pins unconnected. > My understanding from being on the list for a while is that the current > baseband firmware works for some basic use cases on existing phones, Not just for "some basic use cases", but 100% of standard commercial GSM+GPRS modem functionality: if you have a Neo Freerunner made by Openmoko, the Calypso GSM+GPRS modem included in that product provided full commercial quality implementation of all standard GSM and GPRS functionality with the official firmware those units shipped with, and this full functionality is retained without any degradation if you replace their original proprietary firmware with FC Magnetite. Our Magnetite firmware has not been fully deblobbed yet, but: * We have a clear roadmap toward a fully deblobbed version; * I am not currently doing this deblobbed work but am focusing on hardware building instead because I see no point in improving software when there is no practically useful hardware to run it on. > but the end goal of FreeCalypso will require building a phone (or at least > the main board of one). As I said at the beginning of this reply, with ANY libre or FOSS phone goal the real challenge is in the hardware, not software. Right now there are only two pre-existing phone hw units whose hardware is documented well enough to allow running 100% free software including the baseband while retaining the full functionality: 1: Neo Freerunner by Openmoko. This hw is where the original FreeCalypso project started, and has the best support. But the Freerunner is not a bare modem or a dumbphone, it also has a Linux application processor that requires very complex software to make it usable as a phone, and the community that once maintained this complex sw is now gone. Without an active community of developers to maintain that Linux AP software, the Freerunner makes a very poor choice of phone: it is too complex and too power-hungry to serve as a dumbphone substitute, yet it does not really offer anything of practical value that a proper dumbphone can't do, thus it is neither here nor there - "neither fish not meat" as the Russian saying goes. 2: Lower-end members of Motorola C1xx family, including C139. There are no technical obstacles to turning Mot C139 into a 100% FOSS phone by way of FreeCalypso firmware, but the hardware is so feeble that I am not able to justify the required effort. I personally like dumbphones (phones in which the baseband is the sole processor and there is no separate AP or UI processor), and I desire to build a FreeCalypso dumbphone for my own personal satisfaction. But my personal preferences are not the only ones, and if you are building a phone which primarily targets WiFi/VoIP use cases, then obviously you do have a non-baseband application processor. If you need a cellular baseband block which will act as a peripheral in a larger system, you are in the market for a packaged cellular module like SIM900 - but of course all currently existing ones are 100% closed and proprietary. However, if the people who have funded the current FCDEV3B effort wish to continue further in this direction, we can produce a FreeCalypso modem in a packaged form factor similar to SIM900 etc, and the liberated firmware for this mode of operation is already here and 100% functional. > Do the existing basic use cases include sending emergency texts or calls? As I already said, we already have 100% of the standard commercial GSM modem functionality, and of course emergency calls are a part of the standard functionality set. The only caveat is that the emergency call functionality with FreeCalypso firmware has not been tested - making a prank call to a governmental emergency dispatch center is a rather big no-no. > If not, would developing the remaining pieces needed to do so be > substantially easier for an emergency-only use case than for a complete > all-purpose use case? Again, you have a misconception in that there are no missing pieces that remain to be developed, at least for a modem product that is subservient to an external controlling processor - it's all there already. Now if you are talking about a dumbphone product in which there is no external application processor and the Calypso becomes the main and sole processor of the phone, then yes, there is a ton of development to be done - but I have no interest in developing a product that has absolutely no functionality whatsoever except to make emergency calls. > I'm guessing that there are certain parts of FreeCalypso that would not be > required for emergency-only operation (perhaps some of the SIM card > communication, for example), Yes in principle, but the pieces in question are already there and working, hence you would have to do extra work to rip them out in order to satisfy your prejudice against having non-emergency call capabilities. > So I'd be curious to know if the emergency-only use case is substantially > easier to develop for, or if it's roughly the same complexity as developing > for the all-purpose use case, or somewhere in between. In terms of hardware, the two are exactly the same unless you are unwilling to allot the physical space for a SIM socket. In terms of software, the emergency-only use case is more complex because you would have to do extra work to remove perfectly good and working code for non-emergency functionality. I hope my answers clarify things for you a little. Sincerely, Mychaela Falconia, The Mother of FreeCalypso _______________________________________________ Community mailing list [email protected] https://www.freecalypso.org/mailman/listinfo/community
