[Samsung Galaxy Note 9 Questions & Answers] IT_Architect:
Purpose: I named the thread "Expatriate cell phone international portability strategies" not only to answer my questions, but generate a thread focused on general portability strategies, the lay of the land, options, considerations, and how to put together what they need without spending weeks picking up bits at a time. I will toss in what I BELIEVE I know from a couple weeks of reading and research, and request corrections and fill in gaps where needed to make this thread a resource.

Scenario: I am a US citizen, and I plan to live in Colombia and work with orphan kids. I want to maintain seamless US connections as well. I also don't want to go past Oreo until they fix the call recording they broke in Pie. The carriers in Colombia all have GSM roots and their market shares are Claro (48%), Movistar(24%), Tigo(18%) Claro is their Verizon meaning it works even in rural areas and other countries in South America, Tigo has the fastest 3G and 4G speeds, the most 4G, and lowest latencies, while Movistar has some rural areas, it made its name with HD Voice in cities before the others.

The bands in Colombia are:
GSM (2G): 850, 1900 (PCS) - Claro, Movistar, Tigo
UMTS (3G): B2 (1900 PCS) - Claro, Tigo
UMTS (3G): B4 (1700/2100 AWS 1) - Movistar (AWS uses frequencies in several segments between 1695 to 2200 MHz)
LTE (4G): B4 (1700) - Movistar, Tigo, Avantel
LTE (4G): B7 (2600) - Claro, Tigo
LTE (4G): B38 (TD 2600) - DirecTV data
LTE (4G): Future - Colombia will soon (when pigs fly) be auctioning in the 700 range 2x 15MHz blocks (Block A/B12), 2x 10MHz blocks (Block B/B12) and two 2x 5MHz blocks (Blocks C/B12&orB13, and D/B14). A supplementary 2x 2.5MHz block of 1900MHz spectrum will also be auctioned, comprising frequencies in the 1865MHz-1867.5MHz/1945MHz-1947.5MHz bands (Block E/B25).

Strategy Development:

1 The phone must be carrier unlocked. You cannot switch SIMs to another provider in the US or any other country unless the phone is unlocked from the carrier. If you buy a phone through a carrier, you pay for your phone with your monthly payments. They own the phone. You will need to request from them to unlock the phone, which they probably will. If you stop making payments on the phone, they will blacklist the MEID so that whoever has the phone cannot use it, which is how people buy a phone on eBay or Craigslist with a clean MEID and end up later with their phone and phone number being blacklisted for non-payment because the previous owner stopped paying on a phone contract or owes them for service. If you buy a phone outright from a non-carrier source such as Amazon or Walmart, it comes Factory Unlocked because you paid for it, it's yours, and at the time of purchase they don't know which network you will be using it on. *There are exceptions to this. Sometimes Walmart will sell pre-pay phones for a carrier at a deeply discounted rate at which point the phone is locked to the carrier until you spend at least so much on the carrier's network, typically a couple months of service. It will normally state that in the fine print on the box if that is the case.

2. I don't want to get updated past Oreo or some way to preserve call recording. All phones sold for the US market are SM-960U*, and are the same hardware platform thus you can change the model from U to U1 by simply flashing new firmware. The only firmware capable of maintaining Oreo 8.1 without getting forced into an upgrade is the SM-N960U1 Oreo 8.1 firmware, which makes the model of the phone SM-N960U1. You must also do other things to prevent the Play Store from ruining your phone with their malware policies and software updates. You can side-loading earlier versions for software by downloading the APKs from APKPure.com. I subsequently did a thread that spells this out in detail. Restore Call Recording to your Note 9 SM-N960U and SM-N960U1

However, there is another way to get call recording without the cooperation of Android, Play Store, and the phone manufacturer and that is to have a VOIP service host your number(s) and record and backup your calls and logs that puts this entire are outside of their ability to control and monetize your information. This opens up many possibilities such as additional telephone lines for $6.00/mo., local presence in multiple countries around the world with no long distance, your number is protected and isolated from wireless provider control, cheaper data-only SIMs, no number porting, you can pick up a phone anywhere and not be concerned with the number assigned because you won't be using that number, you needn't be concerned that your phone doesn't have the carrier specific firmware for their network to use Voice over LTE (VoLTE) or Voice over Wi-Fi (VoWiFi) because you won't be using it. You will be using VOIP, which can be used by anything that can support a VOIP client, which is PCs, phones, and tablets. One such service that fits that quite nicely is CallHippo for $15.00/mo. With VOIP, if your wireless service lapses, you do not lose your number and you simply need Internet access from anywhere, from any device capable of running a VOIP client to use it, including free hot spots. One thing you want to pay attention to when evaluating VOIP plans is what calls cost. Some have "free" incoming, but for instance with CallHippo there is a limit of 800 minutes/mo. free before they start charging $0.01/minute, and outbound calls always cost money, which in the case of CallHippo is also $0.01/minute. Thus, 1000 minutes will cost you $10.00. VOIP includes hosting your number and switching your traffic across the Public Switched Telephone Network (PSTN) which they are paying for and not being reimbursed for by spying on you as your wireless provider does and "free" services such as Google Voice. Moreover, with regard to Video Calling (ViLTE), many countries have defacto applications people use such as WhatsApp, which is rapidly being replaced by Signal from Open Whisper Systems, for secure calling, video calling, and messaging. The reason for this is in most countries using the public switched telephone network (PSTN) costs more than the cost of the data required a call on Signal, there is never any long distance, all you need is an Internet connection where even a hot spot will do, and unlike with carrier communications where the contents of everything is being monetized, it is 100% secure between callers with no server between that can monitor the content of the communications. Unlike other services, Signal doesn't log the calls or even have the metadata to give even under court order.. Therefore, depending on your strategy, the missing network functionality of not running carrier-specific firmware may be of no consequence. 1 GB of data will do 1200 to 2000 minutes of voice calling, which means the bandwidth requirements are so low, that even when throttled after you use up your data allowance, you will still have at least twice the bandwidth needed for quality voice calls.

3. Doesn't Voice over Wi-Fi really come in handy for International travel? First we need to understand the Public Switched Telephone Network (PSTN) It is a world-wide system that originated with copper wires to central offices near your house. This is called the "Last mile", which might be 3 miles. This also means if you move even across the street or somewhere else where and that location is wired to a different Central Office, your phone number will have to change. With mobile devices that had to change. The cellular carrier provides the "Last Mile" that integrates your telephone number into the PSTN. This costs money, and when you pop a SIM into your phone and pay to make it active, that carrier is now the one getting paid to provide the wireless connection and integrate your phone number into the PSTN and they in fact own the number even if you ported it there. Wi-Fi calling is a VOIP connection to your wireless provider that treats the Internet connection of your phone as though it were another cell tower as you drive down the road and when that signal is better than the one it has, it switches to that one. Therefore, in theory, running your carrier's firmware and Voice over Wi-Fi, you could be in a different country, and still have local cell service over the Internet, but it would have to come from Wi-Fi. HOWEVER, because your wireless provider back home is doing your connection to the PSTN, if you don't have a Wi-Fi connection, and your phone roams without an International plan, it gets very expensive very fast, or calls. If you put a local wireless provider's SIM into your phone, you get a new number local to that country, you lose your connection to your number back home, and calls and messages are stored with your carrier back home, and you are paying for a wireless service that you are not using in order to maintain your number. You can switch back to your carrier's SIM AFTER you connect to a hot spot to return your calls and messages to avoid roaming charges. With a SIM local to the country, your to and from back home would be charged long distance rates. With VOIP, changing to a SIM local to your location or using a Wi-Fi hotspot does not affect your access to your number back home, you are not paying for a service you are not using, VOIP can be used by any SIP/VOIP-client-capable device with any kind of Internet connection, either through a SIM or local Wi-Fi hotspot. Additionally, VOIP presents a stable US number, where nobody back home pays long distance to or from that number, no matter where you are in the world. With VOIP as your PSTN provider and the fact that cellular networks are all now data-based, your "Last Mile" becomes anywhere in the world you can get an Internet connection, whether that be Ethernet, Wi-Fi, cellular, or any combination, and with any device capable of running a SIP/VOIP client, such as a phone, tablet, or computer. Moreover, a lapse of wireless or ISP service, cellular service, or change in country location, does not cause you to lose your telephone number as long as you pay the VOIP provider. So to answer the question, "Doesn't Voice over Wi-Fi really come in handy for International travel?" That depends what your expectations are. First, it requires a Wi-Fi connections, which even when free, requires you to agree to their terms before connecting. This works out well in an airport, airplane, or someplace you may be working whether in US or abroad. In the US it can help inside of a building where reception is poor and you connect to the Wi-Fi. Wi-Fi is not going to work like a cell phone and ring while you are going down the highway or when you don't take the time to find a wireless network to connect to. After you find a wireless connection, you will mostly be working off voicemails, older emails, and older text messages. Popping in a local SIM would cut you off from your wireless services back home but with VOIP, you would have both local access where you are and perfect connectivity back home.

4. Why don't carriers simply use the US UNLOCKED SM-N960U1 firmware? It covers all of the bands for all of the US carriers, and a lot of the rest of the world, both current and future. I can simply change the SIM for the carrier I want, and I'm good to go. Because the U firmware is tailored to the carrier's network which often contains proprietary methods while they were innovating and before standards were established. Thus, those carriers require non-standard firmware to deliver those services in the near-term. The U1 firmware is tailored to current standards. Also, a phone manufacturer has no right to include the intellectual property that a carrier has invested time and money in and is/was used by the carrier for competitive advantage. Therefore, you may be missing some important features of the network by using the U1 firmware, but it will travel better because it is standards-based, but as mentioned above, those missing features may not matter to you. I did a thread that explains that here: US Note 9 Carrier-Specific vs. US Unlocked Firmware Observations & Theories Question: If I use Google Voice, and use a SM-960U1 US Unlocked phone with a local carrier's SIM in Colombia, will I still get VoLTE and carrier banding from the Colombia carrier without their firmware? As mentioned above, that may be of no consequence to you, but carriers are rushing to become standards-compliant both for regulatory and profitability reasons. VoLTE, VoWiFi, messaging, etc. are things they monetize and don't want to turn away people with other phones. Carrier Banding enables them to not only provide better speed, but also more capacity from the very expensive bands they've been licensed by their regulating authority. These affect price and profitability. Thus, the "U" software force you to update to their latest firmware. The "U1" firmware is standards-based already.

5. Google Voice enables me to have VOIP service any time I have a data connection, and if Internet is not available via the data plan or Wi-Fi, incoming calls and text messages are queued for later when I do. It must be a US number and it must have a backup number in the US. I can forward my Verizon number to the Google number, which in turn can forward to multiple other devices to ring, which is essentially free VOIP. (In exchange for your privacy of course.) Their number cross references to my phone book to show who is calling, and their call rings and works exactly like when I get a call to my Verizon number. To avoid spam, you can have it require them to state their name before forwarding the call plus they do a good job of killing off the spammers anyway. If you return their call, you can elect to have their caller ID show your Google number or your home number at the time you place the call. As with non-free VOIP carriers, Google Voice allows you to use the number any way you can get an Internet connection, call anywhere in the US or Canada for free, the best long distance rate if you call elsewhere, and you are not paying a VOIP provider the the month or minute. You don't lose your number for non-payment because you never pay them anyway, BUT you do need to have a US number to back it. It will do incoming call recording but not outgoing, and plays a message that the call is being recorded.

Curiosity got me checking why Samsung uses the Snapdragon processor on all of the US phones, and Samsung's own Exynos on other phones? What I've found, and seems logical is this:

The Exynos chipset, while good on CPU/GPU benchmarking, is still quite weak in radio performance compared to Qualcomm. Qualcomm is still more than one year, possibly even two years ahead, allowing Qualcomm-based devices to use the network more efficiently and make use of advanced network features which are currently relevant for US (to throw some abbreviations here: MIMO, LTE-U, LAA/LWA,etc), and will be for others in the future. Another is the US market still needs CDMA (the predecessor of LTE which is still in use by some carriers). CDMA may have been replaced by LTE-A on the Verizon network, and CDMA scheduled to be shut down EOY 2019, with Sprint EOY 2020, but they still may be using other CDMA networks they have agreements with beyond that. CDMA is not supported by the Exynos modem. The Snapdragon chipset is very power efficient, and Qualcomm develops a lot of good technology and patents. It's hard not to use their chips, and they are priced where you can't afford to compete with them in a level playing field. Intel, who was supplying Apple, threw in the towel and told Apple they were not going to compete with Qualcomm in the 5G world because they couldn't equal their performance and lost money the entire time in the 3G and 4G world. Apple bought their way back into Qualcomm's good graces by repaying a successful law suit against Qualcomm, and signed a 6-year contract. Thus, the processor that made the most sense at this time is the SnapDragon. The US Note 9s use is as well as the Chinese SM-N9600, which unlike the US SM-N960U* has an unlockable boot loader tempting me with a rootable phone and good firmware support in South America, with instances of success working on the Verizon network in the US. The US UNLOCKED SM-N960U1 supports a few more bands than the SM-N9600 and if I root, I lose Samsung Pay. I'm torn on this one.

Looking forward to your input and corrections,

Thanks!