Telna Again?

[andy]

Originally Posted by DRNewcomb

Once long ago I read the details of how multi-IMSI SIMs work. I've forgotten the details. However, I know that at some point the phone tells the SIM the MNN of the network it is attempting to register on. The multi-IMSI SIM can change its personality based on this information. There is really no way for the user to get the SIM to change its behavior. It all has to do with the networks the phone sees when trying to register.

I don't know much about this, but perhaps things vary in the way they've been implemented by different providers

Some multi SIMs come with instructions which mention prefixing the PIN, so one would use 2xxxx or 3xxxx to select the alternate identities, and the 4 digit version will either select the first or the relevant default action.

I don't know whether this applies to all such SIMs. For some types of older phone this is actually necessary whereas for most it's optional.

I have an ekit SIM which recently arrived. Tried out in the UK only so far, by default it selects its Jersey ID, which seems to register only on Orange here. If I prefix the PIN with 2, it selects the Manx ID which roams all UK networks. I haven't tried the 3 prefix for the US ID., but I assume no roaming here.

[LBarouf]

Originally Posted by andy

I don't know much about this, but perhaps things vary in the way they've been implemented by different providers

Some multi SIMs come with instructions which mention prefixing the PIN, so one would use 2xxxx or 3xxxx to select the alternate identities, and the 4 digit version will either select the first or the relevant default action.

I don't know whether this applies to all such SIMs. For some types of older phone this is actually necessary whereas for most it's optional.

I have an ekit SIM which recently arrived. Tried out in the UK only so far, by default it selects its Jersey ID, which seems to register only on Orange here. If I prefix the PIN with 2, it selects the Manx ID which roams all UK networks. I haven't tried the 3 prefix for the US ID., but I assume no roaming here.

Interesting. Since it's in the PIN, it sounds like a STK is running in the USIM software enabling what IMSI to use. Otherwise, automatic selection based on the available PLMNs and in order of the PRL (cheaper first of course!) in the unlikely case where 2 roaming networks are available but from 2 MVNO agreements. But being able to force one particular identity vs the others could be useful if the primary one is unreliable for instance.

Who offers the most IMSIs?