I've been roaming for some time now with my XT SIM in Australia.
Every now and then my phone falls off the network, and calling the XT roaming helpdesk often ends up with me changing a setting within the SIM application for roaming.
In the toolkit, there are two options, TNZ and Sponsor.
Can anyone explain to me the purpose of this? My phone almost always roams on Telstra, but seems to require me to switch between these options from time to time.
Eg, a couple of weeks ago, my phone stopped roaming and the helpdesk advised me to change it to Sponsor. The roaming then started working again. This morning, I noticed the phone was showing emergency calls only, and changing back to TNZ the phone now roams again.
I've never had to do anything like this before when roaming with a VFNZ SIM.