SIM card not working on 2G

[eeuser99991]

I have an old 2G only device (it's an alarm signaller) which works fine.

I recenty tried a newly supplied EE contract SIM in it and it does not work.

Older EE contract & PAYG SIMs seem to work fine in it still.

Is there something different about new EE SIMs that would stop them working in an older device?

Thanks.

[bristolian]

Does that same SIM work OK in other devices? In what way does it not work in the affected device - what are the symptoms?

[eeuser99991]

SIM works fine in other devices.

In the affected device it intermittently shows a signal and sometimes does not and will not send or receive SMS.

[bristolian]

SIM authentication would normally cause an outright "cannot connect" type scenario. Receiving SMS should be automatic once attached.

There certainly shouldn't be any issues with newer SIM, it should be perfectly backwards compatible - but the proof in your case may be in reality!