Announcing project OsmocomBB: Open Source GSM Stack

Harald Welte laforge at
Fri Feb 19 19:02:04 UTC 2010

Good news, everyone [tm]!

I am hereby publicly announcing project OsmocomBB:  A Free and Open Source
software project to create a Free Software GSM baseband firmware.

The baseband chipset is the part of a mobile phone that actuall communicates
directly with the GSM network.  It typically includes a DSP and a
microprocessor running some RTOS, drivers for the baseband chipset,
the GSM protocol stack and some kind of user interface.

GSM has been deployed first 19 years ago.  Despite billions of phones deployed
world wide, all of them run a proprietary baseband firmware, consisting of
proprietary drivers, RTOS and GSM protocol stack.

OsmocomBB has set out to change this.  We do not want our phones to be
a black box connected 24/7 to a public network.  We want to decide what
kind of data our phone reveals about us or not.

The authors behind the project have already spent the last 15 months
implementing an Open Source GSM network side protocol implementation called
OpenBSC.  In January 2010, they decided to go after the phone side protocol
stack - which turned into OsmocomBB.

=> What is the project status?

Right now we are at a state where we have full control over the baseband
hardware, including the DSP and ARM cores, the analog baseband chip,
the RF transceiver, keypad, LCD display and other components.

We can scan the GSM band for cells, perform FCCH detection, run automatic
gain control to synchronize to the cells carrier, detect the SCH to get
BSIC and GSM frame number, as well as dump the BCCH and CCCH of the cell.

=> What does Osmocom mean? 

Open Source MObile COMmunications.  It is meant as an umbrella name for
various FOSS projects related to communications, including OsmocomBB but
also including sister projects like OpenBSC.

=> Can I make phone calls yet?

No. We are currently in Rx (receive) only mode, and have no Layer2 or Layer3
implementation yet.  However, the difficult parts of driving the GMS hardware
and implementing a minimal Layer1 are behind us, so we are confident to proceed
to actual phone calls during the months to come.

=> Where can I get the source?

The git repository is at git://
The mailing lists are at
The project homepage including wiki is at

=> What phones are supported?

We are implementing OsmocomBB as hardware-independent as possible.  At the
moment, we only have drivers for the Ti Calypso Digital Baseband chip.
Our main target are the following Motorola-branded phones (made by Compal):

Adding support for other Calypso-based phones should be relatively easy,
but porting it to a different baseband chip is a lot of work, especially
without access to good documentation.

=> How can you help?

We need developers who have experience in microcontroller development working
on an ARM7TDMI core.  You do not need to know anything about GSM in order to
help us with tasks such as the UI, driving the battery charging controller,
etc.  If you want to join, get yourself a phone, serial cable, join the
developer mailing list and introduce yourself!

Happy Hacking
	Harald Welte

- Harald Welte <laforge at> 
"Privacy in residential applications is a desirable marketing option."
                                                  (ETSI EN 300 175-7 Ch. A6)

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