GSM detection/identification

Paul Buede paul at buede.com
Sun Aug 3 20:00:37 CEST 2008


Paul Buede wrote:
> Matt Joyce wrote:
>   
>> The wiki has some interesting info on GSM :
>> http://wiki.openmoko.org/wiki/Gsm
>>
>> The AT commands to interact with the hardware are here :
>> http://wiki.openmoko.org/wiki/Hardware:AT_Commands
>> (I wonder if they are an extension of the earlier dial up modem
>> commands ala Hayes?)
>>
>> here's how you use the commands:
>> http://wiki.openmoko.org/wiki/Gsmd#Usage_of_shell_mode
>>
>> these command may work for you :
>>
>>         r       Register to network
>>         R       Register to given operator (R=number)
>>         U       Unregister from netowrk
>>         P       Print current operator
>>         N       Print current operator in numeric
>>         L       List available operators
>>         Q       Read signal quality
>>         nr      Query network registration
>>
>> As I mentioned, I wanted to find all contactable sites, but didn't
>> find a command for that.
>>
>>   
>>     
> That was a huge help. What I need now is a way to pass commands from the
> cli and have it return values to the cli rather than operating in the
> shell. So then I can write a script to do it and log to a file. I want
> it to run while I drive around, so I don't have to stop on tap on the
> tiny keyboard. Any suggestions?
>
> I was able to do the following today, from home:
>
> root at om-gta02:/var/volatile/log# libgsmd-tool -m shell
> libgsm-tool - (C) 2006-2007 by Harald Welte and OpenMoko, Inc.
> This program is Free Software and has ABSOLUTELY NO WARRANTY
>
> L
> # # List operators
> 31026 T - Mobile, T - Mob for short, is our current operator
> 31056 Cellular One DC, Cell On for short, is available
> 31041 Cingular, Cingula for short, is available
>
>   
So, I drove around and stopped, and everytime I had any reception at
all, meaning the L gave me any carriers, it gave me the same three
carriers. This modifies my initial theory, and leads to a new one. So,
my new theory is that the SIM card is what allows the phone to see any
carriers at all. And that the three "operators" I could see in my tests
must all allow roaming on each others networks, which is why my T-Mobile
SIM lets me see only those three. I should be able to see Verizon, US
Cellular, and who knows what other operators from some of the places I
tested, including my house.

So, right now, I took the SIM card out, rebooted my phone, and am
testing to see if I can see any carriers at all (doing this from home),
and I see no carriers at all. In fact, here is the output:

root at om-gta02:~# libgsmd-tool -m shell
libgsm-tool - (C) 2006-2007 by Harald Welte and OpenMoko, Inc.
This program is Free Software and has ABSOLUTELY NO WARRANTY

# cme error: 315
L
# List operators
Q
# Signal strength
EVENT: Netreg registration denied
cme error: 32
EVENT: Signal Quality: 11
Signal quality -91 dBm
Error rate undetectable
EVENT: Signal Quality: 9
EVENT: Signal Quality: 11
EVENT: Signal Quality: 9
EVENT: Signal Quality: 11
EVENT: Signal Quality: 9
EVENT: Signal Quality: 11

# L
List operators
cme error: 13

So, I am disappointed. I am going to need SIM cards from other operators
to test reception anywhere. This makes things harder, or at least
slower, as I will have to remove SIM cards and insert new ones at any
given area to test the various carriers. Does anyone else in the US use
a carrier I have not listed as visible with T-Mobile? And would you be
willing to test and see what other carriers you are able to see? Maybe
we can build a list of carrier teams, for lack of a better term. I have
6 days left to back out of my TMobile contract, so I need to get SIM
cards for testing quickly... Will let you all know how it goes.





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