Hi,
I just pushed a "tobias/csd" branch to both the openbsc and libosmo-abis git.
If you check out those branches you should be able to make CSD calls with a BS-11 and the following parameters: V.110, 9.6kbit/s, transparent mode.
The AT-Command to activate this mode is AT+CBST=71,0,0. (If you see an ERROR when entering this command, your phone's baseband most likely doesn't support transparent mode. One of the few exceptions seem to be MediaTek and TI.)
There is no Interworking Function in the code - the V.110 frames simply get sent from one phone to the other. This should not be a problem as long as both sides use the exact same parameters.
The openbsc tobias/csd branch is based on Harald's laforge/csd branch which already adds code for setting CSD channel modes.
Many thanks to Dieter Spaar who found out why I was only seeing garbled data on the uplink, and also to GSMK who let me use lots of my time there to figure out this CSD stuff.
Next stop would be to implement RLP to also support V.110 non-transparent mode which is supported by almost all GSM basebands.
-Tobias
fyi, http://pastebin.com/V8a8c1D7
that's the RLP 'pretty print' I hacked together ...
Cheers,
Sylvain
fyi, http://pastebin.com/V8a8c1D7
that's the RLP 'pretty print' I hacked together ...
Nice, thanks!
-Tobias
Hi Tobias,
On Tue, Oct 09, 2012 at 01:16:59PM +0200, Tobias Engel wrote:
I just pushed a "tobias/csd" branch to both the openbsc and libosmo-abis git.
congratulations to making it work. Sorry for my delayed response, I was completley unavailable in recent weeks.
I've seen teh openbsc.git branch, but I cannot see any branch in libosmo-abis.git. Can you please check if that branch really has been pushed?
Do you see any reason why the code should / could not be merged? From my quick review, I didn't see any ovious location where it would break existing voice call behavior.
Regards, Harald
Hi Harald,
I've seen teh openbsc.git branch, but I cannot see any branch in libosmo-abis.git. Can you please check if that branch really has been pushed?
the libosmo-abis changes have already been merged, so the csd branch was removed - sorry, I should probably have made a mention to the list about that.
Do you see any reason why the code should / could not be merged? From my quick review, I didn't see any ovious location where it would break existing voice call behavior.
I think my changes to handle CSD channels are a hack somewhat since the whole signalling code would probably need an overhaul to properly support different channel types.
But technically everything should (and actually did, for my tests) work fine for voice calls, too, with these changes.
-Tobias
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Harald Welte -
Sylvain Munaut -
Tobias Engel