That'll no doubt be down to the configuration of the terminal device. It'll likely only TX on the available bands allowed in the devices home region for licensi

That'll no doubt be down to the configuration of the terminal device. It'll likely only TX on the available bands allowed in the devices home region for licensing/compliance issues. Back on the tracking side of things... AFAIKR 3G and above do not leak their IMEI/IMSI unencrypted. Of course nearly zero phones show or warn if encryption is used or not (though I think that's a setting in the SIM card).