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NowSMS Support Forums ⬆ NowSMS Support - SMS Issues ⬆ Archive through April 12, 2010 ⬆ |
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| Author | Message | |||
| Roshan Thapa New member Username: Roshan25 Post Number: 7 Registered: 11-2009 |
Is it possible to change imsi by using OTA programming? I think (not sure), we change IMSI by using SIM Explorer but I want to know whether it can be done programmatically over the air or not. Please enlighten me. If it is not possible, I don't want to waste my time in doing reseach and getting to know that it can't be done after 2-3 months of research. Thanks in advance. | |||
| Des - NowSMS Support Board Administrator Username: Desosms Post Number: 1644 Registered: 08-2008 |
Hi, I believe it's possible. I'm not 100% sure. Definitely difficult. As I understand it, the IMSI is stored as a file on the SIM. I took a quick look at ETSI GSM 11.11, and Annex I does indicate that the IMSI file can be changed "over the air", it just has a caution note about doing so. I can't tell you how to do this, as I've never done any of this SIM updating before. You do need the security code(s) for the SIM, so that you can properly encrypt and sign the message. You need to construct an ETSI GSM 11.11/11.14 binary message with a valid security code for encryption. ETSI GSM 03.48 defines the security mechanisms for the encryption of the data. There's also generally UDH (user data header) involved ... 027000. DCS is F6 and PID is 7F. Those are the easy parts ... the tough part is creating the message content to carry out this task. For the specifications that I referenced above ... you can find them at http://www.etsi.org, or more specifically http://pda.etsi.org/pda/queryform.asp. -- Des NowSMS Support | |||
| ashot shahbazian Frequent Contributor Username: Animatele Post Number: 80 Registered: 06-2004 |
Hi Roshan, I've also been told that such OTA-s can be SIM-vendor specific and even specific to different batches of the SIM-s from the same vendor. So unless you've kept track of SIM batches and their IMSI-s you're running a risk of breaking down many SIM-cards. Under normal conditions, the initial failure rate for such OTA reprogramming is roughly 15%, which is in line with the average proportion of Absent active subscribers. Subsequent blasts of OTA-s fix about half of that, so you'd be left with 5-8% of subscribers walking in for SIM replacements. Needless to say: you should not be using a conventional SMSC for such renumbering. It needs to be a high-performance FDA (First Delivery Attempt) gateway. Let me know if you would like us to help: we can recommend a specialised vendor that'd do analysis of your records, contact SIM vendors, construct the messages, bring their SS7 box and connect to your switch to send the OTA-s. It is quite expensive though, up to 20 USD per subscriber. If you can do all of the preparation yourselves and just need an FDA gateway to terminate the OTA-s we can give you SMPP access to it for doing it on your own. That'd cost you standard per-message tariffs, if we have SCCP to your network or you ask your SCCP provider to open it for one of our Global Titles. Kind regards, Ashot | |||
