Hello FreeCalypso community, As most of you probably know, our beloved TI Calypso platform dates from the mid-2000s: the chipset of Calypso C035 DSP36 plus Iota ABB plus Rita RF dates from 2004, whereas most commercial Calypso phones (Mot C1xx, Pirelli DP-L10, Huawei and iWOW modules) date from 2005 to 2007 timeframe. However, the era of "most classic" GSM phones (think Nokia DCT3 family, Ericsson I888 etc) was some years earlier, in the late 1990s - that late 1990s period can perhaps even be called the Golden Age of GSM.
Now that I have my own GSM network for full-freedom testing, I am making a little side venture to enrich my understanding of history: I am acquiring some GSM phones (specifically PCS1900 band models, or multiband ones that include PCS1900) from that late 1990s golden era, I bring them up on my Themyscira Wireless network, and I get a feel for how they function, particularly in comparison to mid-2000s phones which I have more experience with. The first 1990s phone in my collection, acquired just a few days ago, is Ericsson I888 World. This model is a good example of what the term "high end phone" meant in late 1990s - it is a very solid device, big and heavy as a brick. This "world phone" supports just two bands, 900 MHz and PCS1900 - note the lack of DCS1800 support - but back then multiband support was an expensive proposition, requiring large parts of the RF tract to be replicated per band. At the same time as this 900+1900 MHz I888, Ericsson also had a 900+1800 MHz sibling called SH888 - I heard about SH888 being popular in Russia in those days, but naturally it was never found in USA, lacking PCS1900 band support. This Ericsson phone appears to be based on an earlier technology generation than Nokia DCT3 family, even though chronologically they seem to be contemporaries. I don't have any DCT3 phones yet (plan to acquire some, to round out my collection), but some years ago I found Nokia's service manual for "NSE-3 Series", and according to this manual, those DCT3 phones already ran on 2.8V internally: their MAD baseband, their RF block, etc were all powered at 2.8V. The battery was a choice of single-cell Li-ion or 3-cell NiMH, both considered 3.6V nominal. But Ericsson I888 is a higher-voltage beast: it is powered by a 4-cell NiMH battery (4.8V nominal), the scant service manual (much less detailed than Nokia's, unfortunately) mentions expected voltages at a few points, and according to that manual, this very old phone has a baseband running at 3.2V and an RF section running at 3.8V. But aside from internal component evolution in terms of reducing size, weight and power demands, there is remarkably little difference in end user functionality between the awe-inspiring Ericsson I888 and our beloved Calypso: I888 already supports both SIM and "on the phone" phonebook storage, SMS with both storage options once again, and even CSD calls. It has an IR port, presumably proper IrDA, one can presumably do CSD either through this IrDA port or through the wired UART interface on the "system" connector (the kind with many little pins), and there are references to Windows software for manipulating phonebooks and SMS - hence there must be an AT command interface in there. All this stuff, already there in late 1990s! I see these late 1990s high-end phones like this I888 model as the inspiration for what we need to build in FreeCalypso. As I see it, the point in history at which things went wrong was when those 1990s Classic phone manufs, Nokia and Ericsson and others, decided to keep their electronic circuit designs and firmware source proprietary - if classic dumbphone firmwares had been made Free Software back then, the world would have been a much better place. It is now our mission in FreeCalypso to rectify that mistake - yes, we are 25 y too late, but I say better late than never. It is now late hour on my side of the world and I am getting tired, so I won't write much more this time, but I thought I would share my excitement about being able to play with a truly vintage phone and actually get it up and running on my own GSM network. Speaking of my GSM network, as in Themyscira Wireless: I still haven't built the gateway between OsmoMSC's MNCC interface and PSTN, hence we still haven't got outside connectivity - right now it's just calls from one Themyscira phone to another with made-up "extension" numbers, rather than real NANP. I still like the plan of using bulkvs.com service for real 10-digit NANP numbers and PSTN connectivity via SIP, but I have some rather unconventional ideas for how I would like to tie all this stuff in terms of software stack - I will write more later. Hasta la Victoria, Siempre, Mychaela aka The Mother _______________________________________________ Community mailing list Community@freecalypso.org https://www.freecalypso.org/mailman/listinfo/community
