Creating a real usable phone using OsmocomBB

Michael Sokolov msokolov at ivan.Harhan.ORG
Mon Dec 12 17:12:08 UTC 2011


Hello folks,

Just my two cents: one factor that seems to be overlooked in the C1xx
vs. GTA0x decision is the support for different GSM RF bands.  From my
reading of the OsmocomBB wiki, it appears that all those C1xx phones
support only EGSM and DCS1800 bands, but not PCS1900.  It seems like
most current active developers are located in world regions where EGSM
and DCS1800 bands are used, but in my area the only usable GSM band is
PCS1900, or maybe GSM850 too: haven't been able to try the latter as I
don't have any devices that support it.

OTOH, my Neo Freerunner (which is currently doing shelf duty as a
paperweight lacking functional source-enabled Calypso fw) supports the
PCS1900 band in addition to EGSM and DCS1800.

But if the community goes the C1xx route and produces GPL code that
runs fully on the Calypso, no PC needed, does power mgmt and
implements some UI on the Calypso-controlled LCD and keypad, I expect
no difficulty with taking that code, replacing the Calypso-based UI
with some simple protocol for interfacing with the UI over the modem
UART (maybe not the same as the infamous AT command interface, but
doing the same job on the same level of abstraction), and running it
on my GTA02, hence I'm not complaining.

As far as the power management etc advantages of the simpler phones
without an application processor: does anyone know of any basic
Leonardo-style phones which are like the famous C1xx, but support the
PCS1900 band, are physically available, and documented no worse than
C1xx in terms of the availability of schematics and docs for display
and other non-Calypso components?

The fact that C1xx phones can be bought in 1000 unit quantities is
great news for those living in areas with EGSM/DCS1800 services, but
doesn't do much good for those living in PCS1900/GSM850 lands...

MS




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