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Michael Spacefalcon msokolov at ivan.Harhan.ORGAs I wrote here two months ago, I am seeking to build my own totally free, end-user-usable Calypso-based quad-band GSM plain phone, as well as possibly a Calypso-based free GSM modem module for smartphone projects done by others, such as this: http://talk.maemo.org/showthread.php?p=1376708 I already have the Calypso etc chips in qty 100 sitting in my desk drawer - buying them on the Chinese surplus market turned out to be surprisingly easy, and they most definitely have quite a bit more of them available than the 100 I have bought. Making my GSM device(s) quad-band as in 850/900/1800/1900 MHz is an important part of my goal - contrast with the current OsmocomBB- supported devices, which are only dual-band or tri-band at best. My belief in the idea that our familiar Calypso/Iota/Rita chipset is capable of supporting the quad-band configuration stems from the existence of this TI reference design: ftp://ftp.ifctf.org/pub/GSM/Calypso/Leonardo_plus_RD122.pdf ftp://ftp.ifctf.org/pub/GSM/Calypso/Leonardo_plus_quadband_schem.pdf ftp://ftp.ifctf.org/pub/GSM/Calypso/M034F.pdf The first PDF is something I just found on 52rd.com 2 days ago: it has the Leonardo+ quad-band schematics plus a component placement drawing. The 2nd PDF is the schematic which we have had for 2y now (might be a very slightly different version, haven't visually diffed the two closely enough) and the last PDF is for the quad-band RF FEM they used, all from 52rd.com. What I am still missing is a copy of the PCB layout (in whatever format TI used for their reference designs all those years ago) corresponding to those schematics. I have not yet found that article in my trawls through 52rd.com - that's a search for a needle in a giant haystack. (We also have a Leonardo_rev05.dsn file, in the same directory as the ones listed above, but I assume it's the EDA source file for the schematic capture phase only, no layout.) I have already found a layout for a dual-band phone on an 8-layer PCB: ftp://ftp.ifctf.org/pub/GSM/PCB/unknown-phone-pcb1.zip and I can probably find a layout for a tri-band phone on an 8-layer PCB too, something like Pirelli DP-L10. In contrast, Leonardo+ is a very elegant quad-band design, and this TI doc says it's only a 6-layer PCB: ftp://ftp.ifctf.org/pub/GSM/Calypso/chipsets+refdesigns.pdf (see page 10) We also have this: http://scottn.us/downloads/peek/HW%20doc/I-Sample%20ref.%20design/Full%20package%20-%20I-sample%202.7/ I-sample is TI's LoCosto board, and it is quad-band. But LoCosto's built-in RF block has separate LNA inputs for 850 and 900 MHz unlike Rita, and I-sample uses a weird arrangement: the PA and the antenna switch are integrated into one, but the Rx SAW filters are discrete. So it isn't the same as Leonardo+. Thus I am putting out this loud call for anyone who may have found a copy of the Leonardo+ PCB layout somewhere on 52rd.com or some other site of a similar nature. If you have a copy of this PCB layout or know of a place where it can be downloaded, please speak up! By helping me obtain a copy of that PCB layout, you would be helping not only me, but also all those end users who would appreciate having a quad-band GSM plain phone (or a modem for Neo900 etc) that is fully documented and capable of running 100% free baseband firmware. TIA, SF