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| USA 3G sunset - swapping SIM could create headache |
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| Rick Law:
In my opinion, eSIM rather missed the point of having a SIM at all. Before this 4G era, the SIM is the portable "personality card" for your phone. Inserting that card into a phone and that phone instantly becomes your phone. Twice I dropped my phone in water. I just wiped the SIM clean, put it in another phone and off I go - another phone with my phone number and contact list. eSIM (non-portable) would remove that portability. Decades ago (early 2G era) after my first business trip to Europe, I got off Verizon (CDMA, no SIM so it was eSIM of that era) and migrated to AT&T (2nd line T-Mobile) for the flexibility of GSM SIM-portability. Subsequent trips I have my unlocked GSM phone. I can use any GSM carrier's SIM on the same phone. While overseas, I can also use a local-SIM and make local calls rather than via my USA-carrier. Same physical phone with many personalities suitable for the occasion. That said, 4G/LTE (to be precise, VoLTE, aka HD-Voice) will make cross-carrier portability difficult. Unconfirmed but as I understand it: VoLTE on AT&T and T-Mobile are not the same. So "carrier unlocked phone" may no longer ensure it will work on both AT&T and T-Mobile anymore. |
| chickenHeadKnob:
--- Quote from: SteveyG on July 20, 2021, 12:00:53 pm --- --- Quote from: rsjsouza on July 20, 2021, 11:12:17 am --- --- Quote from: SteveyG on July 20, 2021, 09:04:38 am ---What's with this recent use of the term "sunset" ??? Strange one. --- End quote --- I have been hearing this word used in this sense for about twenty years. It is just one more way of saying a cold hard truth in a soft way so as to not hurt the feelings of whomever is on the other side of the conversation. :-// --- End quote --- The sun rises again though the next day... :-// Surely phasing out or retiring is more applicable. --- End quote --- I'm old, as in sixty+. I encountered "sunset clause" as legal jargon concerning contracts going back more than 40 years. It is nothing new and has nothing to do with fee-feels you may be having. |
| tooki:
--- Quote from: SiliconWizard on July 20, 2021, 08:08:41 pm --- --- Quote from: tooki on July 20, 2021, 07:59:29 pm ---I think this also exemplifies a few things, including the complexity of SIM cards (which aren’t just dumb storage devices, nor even “just” encryption processors: they’re full application processors that run carrier applications), and that the network itself has complexity we don’t see. --- End quote --- Speaking of which, there are now phones and networks that can operate without a physical SIM card. That's called eSIM. It's a virtual SIM card running on the processor, and it embeds much more information than traditional SIM cards as far as I've understood. eSIM is probably going to replace SIM cards completely. --- End quote --- Yep, though as far as I know, it’s actually a dedicated embedded processor, since it is responsible for network security. |
| tooki:
--- Quote from: Rick Law on July 21, 2021, 12:06:01 am ---In my opinion, eSIM rather missed the point of having a SIM at all. Before this 4G era, the SIM is the portable "personality card" for your phone. Inserting that card into a phone and that phone instantly becomes your phone. --- End quote --- Well, it still is, both in the 4G and 5G eras, for the vast majority of users. --- Quote from: Rick Law on July 21, 2021, 12:06:01 am ---That said, 4G/LTE (to be precise, VoLTE, aka HD-Voice) will make cross-carrier portability difficult. Unconfirmed but as I understand it: VoLTE on AT&T and T-Mobile are not the same. So "carrier unlocked phone" may no longer ensure it will work on both AT&T and T-Mobile anymore. --- End quote --- Whoa there. You’re confounding multiple things. VoLTE ≠ HD Voice. Higher-bandwidth voice calling exists on 3G and even 2G networks, too. The specific implementation called “HD Voice” requires VoLTE, but not all VoLTE carriers and phones support it. And many carriers do not support high-bandwidth calls to other carriers, even if they use the same standard. As for carrier locking: most carriers stopped that nonsense anyway, but HD voice support has NOTHING to do with this. The phones support what they support, the carriers support what they support, and the carriers’ peering support varies, so you end up with whatever the weakest link is for a given call. EDIT: Closer inspection reveals that the "HD Voice" trademark specifically requires the use of the AMR-WB codec, but it can be implemented on any network type, not just VoLTE. |
| Rick Law:
--- Quote from: tooki on July 21, 2021, 05:07:16 pm ---... ... --- Quote from: Rick Law on July 21, 2021, 12:06:01 am ---That said, 4G/LTE (to be precise, VoLTE, aka HD-Voice) will make cross-carrier portability difficult. Unconfirmed but as I understand it: VoLTE on AT&T and T-Mobile are not the same. So "carrier unlocked phone" may no longer ensure it will work on both AT&T and T-Mobile anymore. --- End quote --- Whoa there. You’re confounding multiple things. VoLTE ≠ HD Voice. Higher-bandwidth voice calling exists on 3G and even 2G networks, too. The specific implementation called “HD Voice” requires VoLTE, but not all VoLTE carriers and phones support it. And many carriers do not support high-bandwidth calls to other carriers, even if they use the same standard. As for carrier locking: most carriers stopped that nonsense anyway, but HD voice support has NOTHING to do with this. The phones support what they support, the carriers support what they support, and the carriers’ peering support varies, so you end up with whatever the weakest link is for a given call. --- End quote --- You are right, I should not have put it as "VoLTE aka HD Voice". As to carrier-lock on phones, most US carriers are still locking phones, but they hardly offer the discounts they used to anymore. With "HD voice" implementation differing from carrier to carrier, an unlocked phone would need to support most major carriers' implementation, otherwise the phone wont work. That makes shopping for unlocked phone a bit more complicated: not just the right frequencies support, now one more factor that must be compatible. |
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