i'm not that familiar with the tech details of our northern neighbour telecoms - i have a digi card, so i normally swap it in when crossing over - never tried any testing before because it just works. First time in a long time with IDD calls on roaming. so.....
ST line was roaming, but not data roaming coz I've a Hotlink card in the same phone.
Oh, is that the reason, VoLTE not turned on for ST line coz it wasn't data roaming?
i believe you need VoLTE up north to make calls (VoLTE is normally a default when selecting 4G and higher for recent phones. it's the older phones that normally have the VoLTE switch)
On my phone, VoLTE calls can still connect even though the phone mobile data is turned off- i may be wrong, but i believe this is a feature for 4G/5G networks.
purely guessing: if phone is on home/local network, then it works, but if roaming and no data roaming, then maybe that is enough to prevent the call from getting thru.
time to make a trip to woodlands to test, hopefully the signal spillover is strong enough.
Like I said, I've no intention to make overseas calls with this line, so didn't read up on 8's limitations on its usage. Was just trying coz someone asked to.
"Thank you for your service"
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