Hello fellow Calypso phone hackers, Not having found an already-existing Calypso phone that is exactly to my liking (of the ones supported by OsmocomBB, the Pirelli comes closest to my ideal, but even that one has a few things I don't like, and most important of all, the availability of these phones on the market has already shrunk down to zilch - so the day is near when it will be just as legendary-unobtainium as the TSM30), I am setting out to build my own. I am setting out to design and build a new Calypso/Iota/Rita phone, one that will be specifically designed to run Free Software as its firmware: either OsmocomBB or FreeCalypso (my own personal alternative free GSM firmware implementation), up to each user's individual choice. My design will be a phone, not a modem (i.e., complete with the essential UI elements, as in LCD and keypad), and it will be a dumb/plain/feature phone, i.e., the Calypso will be the main/sole CPU - not a smartphone like Openmoko etc. Before I tackle the difficult problem of either making a new plastic case or choosing some existing one, I will start out by building a bare GSM development board - basically a complete phone sans case, built on a non-form-factor-controlled PCB. This development board will probably end up being very similar to the one which Harard Welte has announced here a little over a year ago, but with one major difference: *all* hardware design source files (as in schematic, BOM and PCB layout source) will be openly released, with absolutely nothing withheld, and in fact the development itself will take place in a public source control repository. Therefore, regardless of whether I succeed or fail in the ultimate goal of producing a complete phone packaged in a plastic case, there will be an Open Source Hardware design for a working Calypso GSM board which others will be able to use as a starting point - something that wouldn't be possible (or at least less convenient) with Harald's PDF-schematics-only version. However, the above vaporware announcement is not the real purpose of my post. Instead, I am currently in the negotiations with several Chinese sellers of Calypso/Iota/Rita/etc chips, and I'm soliciting advice on exactly which variant of each chip I should use: * The Calypso chip in both GTA02 and Pirelli DP-L10 (the two existing designs I use as references to be copied whenever it makes sense) is PD751992AZHH. I can easily get this exact part, but I can also get ones with GHH or AGHH suffixes. I'm venturing a guess in that the A seems to go with the 751992 number, i.e., it's part of the die revision, and as to the difference between GHH and ZHH, I'm guessing that it's the RoHS difference: I'm guessing that GHH has balls made of real SnPb solder, whereas ZHH has the "lead-free solder" junk substituted instead. Because I'm very fortunate to NOT live in the EU or anywhere near, I'm not subject to any EU-nian laws like the RoHS idiocy, and I generally prefer to use real SnPb solder whenever possible. So I wonder: can someone confirm if indeed PD751992AGHH is the exact same Calypso chip as the PD751992AZHH used in the GTA02 and Pirelli phones, but with real non-RoHS solder balls instead, or is it something different? * Which Iota variant is better: TWL3014 or TWL3025? I'm thinking TWL3025, reasoning that it being newer probably means having some internal bugfixes or minor improvements, but perhaps the older TWL3014 is better instead? * As to the Rita, the base part number appears to be TRF6151C in all phones currently supported by OsmocomBB, so I'm sticking with this base part number. But there are additional suffixes after the 'C' in that P/N - would anyone happen to know what these suffixes mean, and which variant I should use? * For the RF PA, I see that the GTA02 uses RF3166 from RF Micro Devices (one of Harald Welte's posts regarding his planned Calypso board also mentioned him planning to use the same PA), whereas the Pirelli and most other feature phones supported by OsmocomBB tend to use Skyworks parts instead. Which is better? I'm currently leaning toward the RF3166, but if someone has a recommendation that is actually backed by some knowledge/reason rather than just a guess like mine, I'll listen. :-) * If I do go with the RF3166, any idea as to what the different suffix versions are? TIA for any input, SF