FlyerTalk Forums - View Single Post - Can I get another sim card (same number) and use it in two devices at once?

Mar 21, 2006 | 7:23 am

#25

roberto99

Join Date: May 2001

Location: exUA1K, UA MM, lifetime UA1P, AA MM, HH Diamond, Marriott Gold

Posts: 3,803

Quote:

Originally Posted by ScottC

IMEI's have nothing to do with Sim cloning.

The IMEI is written in the device, in a sim clone it is the IMSI that gets copied. For an "official" multisim they simply provide you with 2 sims with the same IMSI, usually with A and B stamped on the back. Other than that the sims are identical. I've never heard of an operator having to "authorize" IMEI's, the nice thing about GSM is that you can use as many IMEI's as you want, all the operator cares about is the IMSI which it has stored away safely in its systems. The sim sends a challenge-response style temporary version of the IMSI, but in the case of 2 sims it is still based on the same number....

I've read that in the UK, phone IMEI's can be barred or blacklisted by certain or all carriers to prevent lost or stolen or defaulted accounts from functioning.

So perhaps the IMEI CAN be used along with the IMSI for authentication. I think that this is NOT the case in the USA.

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