among the NEW iPhone Xs Max, Apple has release a unique Model A2104 for China and Hong Kong ONLY, which has physically TWO SIM card slots instead of the normal one-eSiM and one micro-SiM slot . while this mostly has to do with the former colony’s dual life and business-style, users around the World can purchase this to put TWO numbers in their phone . however, this does NOT mean you can get all the perks for each phone number separately in every country .

 

as for South Korea, I have long-ago mentioned the use to TWO phone numbers even from before the age of Smart-Phones and iPhones here (via some number-crunching on earlier models). this has been possible by pressing a couple of numbers BEFORE the actual destination phone number which has been called “Number Plus” on all major local carriers – whose ability was embedded into the phone since all phones were made for specific carriers .

all this has evolve into a more “clever” and automatic optional service only works ON either LG or SamSung phone, signed-onto KT(Two-Number), SKT(Number Plus) or LGT/Uplus(Dual Number) . and since phones aren’t carrier-locked from Galaxy 9, the ability comes from the carrier’s SIM card . KT phones has a switch number on Top-Right of the screen like (1) and (2), while SKT and LGT use additional Android App.where you can send and receive calls AND messages .

the difference between the former and latter service is that :

  1. while the former used temporary second-number, the newer service offers actual phone number in Korean telecommunications registry
  2. you can use separate Kakao, LiNE, WeChat and WhatsApp account for each number !
  3. the price for this optional service remains similar before-and-after and among all major carriers – about W3,000~4,000 per Month .

 

now according to early-adopters who have bought Chinese and Hong Kong iPhone Xs Max (simple Xs don’t have physical Dual-SiM slots – ONLY Max does) in Korean and Chinese carrier SIM cards :

  • switching between the two numbers on-the-fly input on a single page in iPhone Systems
  • works with one Chinese number and one Korean number, where the former will be international roaming in South Korea
  • but cannot use different SNS accounts as with existing Korean services mentioned on above paragraph (as the services notice it is the same device)

 

※note though, not verified yet : according to Apple’s Official LTE Model comparison page, “Hong Kong models are specifically adapted to Hong Kong usage surroundings” which have now disappeared – which is why FaceTime seem to work only on Hong Kong models and NOT Chinese (their model number is the same A1204).

– six phones and twelve numbers in total, Korea Tech BLog –