Opps, forgot to answer one question :<br /><br />&gt; My main concern is logistics.  I doubt you have BIPT approval to accept IMSIs<br />&gt; not registered with you.  How will you get people to register?  <br /><br />The same thing that @ 26c3. Basically people have to pre-register on a website. Either their IMEI (via *#06#), or their IMSI if they know it.<br /><br />Then on the network, when a phone tries to register :<br /> - We ask for both IMSI & IMEI<br /> - If the IMSI is allowed, we accept the user<br /> - If the IMEI is allowed, we mark the current IMSI as allowed in the DB and accept the user<br /> - If none of the above, we send a temporary congestion error. (the phone will then try other operators / bts and work normally).<br /><br />Cheers,<br /><br />  Sylvain