hi,
i dont know if this is the right place to ask this question but i thought i might ask...any help would be much appreciated.
i am using a GSM modem specifically SIM300 and the sim is not registering to the network...i checked it using the AT+CREG? command and it returns +CREG:0,2 which means it is searching for an operator to register to. after sometime on the query again i get +CREG:0,0 which means it is no longer searching for an operator. it is a new sim(tata docomo) which works fine in a cell phone. when i use a sim from a different operator(vodafone) it is registering.
i googled for this problem and i could see one other person who faced this problem but there was no solution provided there.
if you have a solution or any troubleshooting please let me know. thanks in advance!
Do you have a proper antenna on the modem? What signal strength do you see? AT+CSQ Does the SIM support data? or voice only? Does the operator support/permit the modem? That work in other modems? Have you tried other SIMs?
hi thanks for your reply...antenna and signal strength are proper AT+CSQ returns a signal strength of 31.0(excellent according to a diagnostic tool i am using)
m2msupport.net/.../
what i dont understand is that it is registering with different sim.
the sim supports both data and voice.
how do i find out if the operator supports the gsm modem?
i have tried a different sim and it works.
"i dont know if this is the right place to ask this question"
No, it isn't - it doesn't have anything to do with Keil, does it?
Anyhow...
"how do i find out if the operator supports the gsm modem?"
Err, isn't the obvious answer to that, Ask The Operator?!
Yes, it is the case that operators will sometimes refuse registration to "unknown" devices - so you really do need to ask the service provider.
Is the SIM from a proper M2M provider?
Trying to get support from a consumer/telephone provider is (almost) doomed to failure - they just don't understand...
i know it doesnt have anything to do with keil but i didnt think there was any harm in asking since i have already seen posts like mine...didnt think there would be any keil police here.
i have already asked the operator but they didnt have a clue what i was talking about...i was just wondering if someone else has faced this problem and that they might have a solution
the sim is from a valid M2M provider...i am able to use it in a cell phone
So does the SIM card subscription match the type of bands your module supports? A 4G SIM with a 3G module isn't a hit even if the SIM works when put in a 4G phone.
@per westermark - i thought you might join in sometime :)...thanks for your reply
i dont follow...even if the sim is 4G(in my case its not), shouldnt it still register on the network with the modem if the bands are the same? 4G service will not be available for sure. btw i have a 3G sim and phone and so is the modem.
if i use a different sim then it is able to register...seems to me that the problem lies with the sim provider itself? or maybe the modem doesnt support this sim? i have only 2 types of sims so cant say for sure though...also my knowledge of GSM is quite poor at this point of time so i do not know any troubleshooting techniques...
additionally if i search for the networks available with AT+COPS=? then i am not able to see the operator in the returned results even though it registers to the correct operator in the phone automatically.
The content/configuration of a specific SIM may limit it's ability to register and/or roam on the available networks.
The firmware on the SIM300 may also be old, or not certified by the network. The network may choose to eject you based on the IMEI or SIM# (IMSI/ICCID)
Have you tried reading the SIM# from the modem? AT#CIMI AT#CCID
Does the modem's ability to register do the same thing if you just remove the SIM completely?
Even with a voice only SIM, most modems can register with the network and place calls/sms, if data is explicitly excluded you will not be able to open a data context/connection.
@westonsupermare pier - thanks for replying again
here is what response i get when i execute the 2 commands
AT+CCID 89910341610344270127
OK AT+CIMI 405034034427012
OK
it also has a valid IMEI but i just found out that the number mentioned on the GSM module and the number returned by AT+CSGN? command are not the same. could this be a problem? The IMEI returned by the command,352360000020000, is valid which i checked using this link imei-number.com/.../. the other IMEI is valid as well.
i didnt get your meaning but if you are asking me what happens if i remove the sim and then turn on the modem then it shows sim not inserted of course...even as i am writing this i think that is not what you meant...
Yes, I meant take out the SIM, and observe the CREG status over time. Does it result in not registered, not looking?
If the modem and/or SIM are not compatible with each other, you'll have to change one of them until they are.
If you are talking to front-line support staff at the network they are likely to be next to useless in resolving any incompatibility issues. You'd need to find someone specializing in M2M applications, and network support thereof, and modems approved for network use.
@Westonsupermare Pier after taking out the sim it does not register..it returns +CREG : 0, 0. this was expected since without a sim it will not register on the network.
i understand that i will have to change the sim/modem until i solve this problem...right now changing the sim seems to be a good idea but i was looking for that particular provider since they provide the lowest rate on a data plan...
anyway thanks for your support...will post the solution here if i find it.